Before paid growth pretends it pays for itself
SaaS Magic Number: Sales Efficiency as a Growth Tripwire
A rising revenue slide that never mentions what sales and marketing cost is not validation. The SaaS Magic Number asks a smaller, honester question: how efficiently did last period’s S&M spend turn into incremental subscription revenue? Write that efficiency tripwire before you look. Matching it is a decision signal — not a forecast that you will succeed, and not a substitute for naming the weakest demand or retention assumption first.
Last updated: October 15, 2026
Direct answer
What is the SaaS Magic Number — and why write the tripwire first?
The SaaS Magic Number estimates how efficiently sales and marketing spend turns into incremental subscription revenue. The classic Scale formula takes the change in subscription (GAAP) revenue between two quarters, annualizes it (×4), and divides by S&M spend in the earlier quarter. Higher is more efficient. Matching or missing a pre-written efficiency tripwire is a decision signal — not a prediction that you will succeed.
Key takeaways
What to remember
- Magic Number = [(Revenue_Q − Revenue_Q−1) × 4] ÷ S&M_Q−1. Scale’s Rory O’Driscoll (20 April 2010) uses GAAP revenue change, annualized, over prior-quarter S&M — not S&M as a percent of this quarter’s revenue.
- Scale’s 2010 bands, used as written: greater than 1x is a compelling business investment; below 0.5x means the company still has not figured out its model; between 0.5x and 1x may reach success and cash-flow breakeven, but in a relatively capital-inefficient way. The metric is deliberately simple. Its virtue is GAAP comparability.
- Dale Chang / Scale (8 September 2020) separates Gross Sales Efficiency (Gross New ARR ÷ same-period S&M), Net Sales Efficiency (Net New ARR ÷ same-period S&M), and Magic Number (the GAAP workaround with a one-quarter lag). Scale Studio’s long-term median Magic Number among 1,000+ growth-stage SaaS/cloud businesses sits around 0.7 — Scale’s dataset, not a universal law. Above 1 is rare and attractive to investors.
- First Round’s Levels of PMF (8 April 2024), written for sales-led B2B, puts magic number inside Efficiency (with CAC, CAC payback, NRR, gross margin, and burn multiple). Level 3: magic number >.75 and CAC payback <18 months. Level 4: magic number >1 and CAC payback <12 months. Level 1 names no Magic Number. Those are labeled Level marks, not a law for every consumer app.
- Write signal + threshold + calendar window + named action (scale S&M / hold / cut paid channels / keep testing organic) before you measure. Prefer the trend across periods over one heroic quarter. A Yibud score is not Magic Number and not a success prediction.
Why it matters
Why S&M% of current revenue lies to a subscription company
Founders steal a product-company habit: divide this quarter’s sales and marketing by this quarter’s revenue and call the percentage “efficiency.” For SaaS, that ratio is mostly a picture of the annuity you already sold. Two published sources are useful here as instruments, not as personal odds: Scale on why the relationship has to be prior-period S&M versus the change in revenue that shows up afterward, and First Round on why sales efficiency belongs in a product-market-fit conversation at all.
The S&M% trap — O’Driscoll, not a new taxonomy
Product companies recognize revenue soon after a sale, so S&M as a percent of current revenue is a usable approximation of efficiency. Subscription companies book customers now and recognize revenue over the contract. This quarter’s revenue is mostly last year’s selling, now showing up as an annuity — not a fair proxy for this quarter’s S&M. O’Driscoll’s correct relationship: prior-quarter S&M versus the change in revenue that shows up afterward. This page does not invent a second formula.
Efficiency is part of First Round’s PMF definition
First Round’s Levels of PMF (published 8 April 2024) is written for sales-led B2B. Efficiency includes finding the customer (CAC), selling and closing (sales conversion, magic number, CAC payback), activating and supporting (NRR), producing (gross margin), and company-level burn multiple. Demand without a path to efficient delivery is the roadside-stand mirage on their page. Keep the caveat: their Level numbers are not a law for every consumer app.
The four terms
Gross SE, Net SE, Magic Number, tripwire
These four fields are the instrument. If any one is fuzzy, the number is a slide, not a tripwire. This page does not publish a grade table beyond Scale’s three 2010 bands and First Round’s labeled Levels. Use those, then write your own bar.
Gross Sales Efficiency — new ARR with no losses in the picture
Gross New ARR in the period divided by the same period’s sales and marketing. Dale Chang / Scale (8 September 2020): no churn or downsell adjustment. It is a clean look at how the GTM engine added, not at what leaked. Do not treat it as Magic Number. Do not treat it as proof you will succeed.
Net Sales Efficiency — new ARR after the leaks
Net New ARR in the period — new sales minus lost business — divided by the same period’s S&M. Scale’s primer: one number that includes wins and losses. Useful internally when your ARR definition is stable. Still not the GAAP Magic Number boards use to compare companies.
Magic Number — GAAP revenue change, annualized, over prior-quarter S&M
Scale’s workaround when ARR definitions vary: take the difference in GAAP (subscription) revenue between two consecutive quarters, multiply by four, and divide by S&M in the earlier quarter. The lag is the point. Same-quarter S&M over same-quarter revenue is a different choice — state it if you make it. Prefer excluding stock-based compensation from the S&M denominator when you are reading GAAP lines (Scale’s preference).
The tripwire — written before you measure
Signal + threshold + calendar window + named action (scale S&M / hold / cut paid channels / keep testing organic). Write it on a dated page before the first period report. A kinder bar after the results is a recap, not a tripwire. Matching the bar is a decision aid. It does not prove you will succeed.
Scale’s formula and bands
>1x, 0.5–1x, <0.5x — plus a Studio median that is not a law
O’Driscoll wrote the formula and the three bands on 20 April 2010. Chang’s 2020 primer restates Magic Number as the GAAP stand-in for Net Sales Efficiency and adds Scale Studio context. Use the numbers as they wrote them. Do not paste a later five-tier grade chart onto this page and call it Scale’s.
The formula: annualize the change, divide by earlier-quarter S&M
Take the change in subscription revenue between two quarters, annualize it (multiply by four), and divide by sales and marketing spend for the earlier of the two quarters. Written out: Magic Number = [(Revenue_Q − Revenue_Q−1) × 4] ÷ S&M_Q−1. You spend the cash, then the annuity shows up. Pairing this quarter’s S&M with this quarter’s revenue line skips that lag unless you say so out loud.
The 2010 bands: >1x, 0.5–1x, <0.5x
Greater than 1x has proven, in Scale’s 2010 telling, a compelling business investment. Below 0.5x is a company that still has not figured out its model. Between 0.5x and 1x is a deal that will probably get to success and cash-flow breakeven, but only in a relatively capital-inefficient way. Those are Scale’s three bands. This page does not invent a fourth.
Simple on purpose — GAAP is the redeeming virtue
O’Driscoll is explicit: the metric does not unpack churn, gross margin, or new sales versus upsells. CAC, MRR, and ACV are more specific. Magic Number wins because it is GAAP-based, available for public companies, and comparable when nobody will share internal churn or rep-productivity definitions. If you fudge GAAP, you go to prison — his line, not ours. Use it as a comparable efficiency sitting, not as a complete operating system.
Scale Studio context, 8 September 2020, labeled as Scale’s dataset rather than a law of nature: among 1,000+ growth-stage SaaS and cloud businesses, the long-term median Magic Number sits around 0.7 — about $0.70 of new ARR per $1 of S&M. Companies with Magic Number above 1 are rare; Chang calls that unique and attractive to investors. Prefer excluding stock-based compensation from the S&M denominator when the line is GAAP.
Stickiness note from the same primer: after about $10M in sales, sales efficiency often persists. Build an efficient GTM early. Some companies do rewire later. Do not count on a late rewiring as the plan.
Published Level marks
First Round Levels — Magic Number where they name it
First Round publishes these as Level benchmarks for sales-led B2B, not as a law you must hit next quarter. Use them as a vocabulary for “how serious is sales efficiency at this Level,” then write your own tripwire for the periods you can actually measure. Do not paste Level 4’s >1 onto a pre-seed consumer idea and call it research. Level 1 does not name a Magic Number; this table says N/A rather than inventing one.
| Level (First Round) | Magic Number they name | How they frame it |
|---|---|---|
| Level 1 — Nascent | N/A — not named | Efficiency comes last. They do not publish a Magic Number threshold at this Level. Gross margin and burn multiple are often N/A too. Source: First Round, Levels of PMF, 8 April 2024. |
| Level 2 — Developing | .5 to .75 (they write ARR/CAC) | They parenthetically write “Magic Number” as ARR/CAC in this band. That is their Level-2 mark, not Scale’s GAAP formula. Source: First Round, Levels of PMF, 8 April 2024. |
| Level 3 — Strong | >.75 | Magic number >.75 and CAC payback <18 months. This is also where they say you have to get serious about efficient economics. Source: First Round, Levels of PMF, 8 April 2024. |
| Level 4 — Extreme | >1 | Magic number >1 and CAC payback <12 months. Source: First Round, Levels of PMF, 8 April 2024. |
Scale’s Magic Number is annualized GAAP revenue change over prior-quarter S&M. First Round’s Level 2 line writes ARR/CAC in parentheses. Do not flatten those into one homemade grade table. Label the source when you quote a band.
Scope note, from the same essay: the framework is written for sales-led B2B. First Round is explicit that the hunt for product-market fit is more of a dice game for consumer apps. Do not claim these Magic Number marks as universal.
How to run it
How to measure Magic Number without faking LTV
This is Yibud’s suggested sequence, not a Scale checklist and not a First Round law. Honor the tripwire you wrote before the first report. If you cannot name the decision the number would change, you are building a slide.
- 1
Pick two consecutive periods and honor the lag
Two quarters is the classic Scale sitting. Months work if you keep the same lag logic: prior-period S&M versus the change in revenue that shows up afterward. Name the dates. For an internal Net SE view, you can use Net New ARR over same-period S&M — say so. Do not mix Q3 S&M with trailing-twelve-month revenue and call it Magic Number.
- 2
Write the tripwire before you look
Signal is the Magic Number (or its direction versus the last pair of periods). Threshold is the miss / pass line you will honor — Scale’s <0.5x floor, Scale’s >1x scale-up bar, or a bar you write for this decision. Window is the calendar close. Action is scale S&M, hold, cut paid channels, or keep testing organic. Do not rewrite the bar after the report.
- 3
Prefer the trend across periods over one heroic quarter
One cheap quarter after a brutal one is not the story. Q1→Q2 versus Q2→Q3 on the same definition tells you if sales efficiency is improving or collapsing. Headline revenue can still rise while Magic Number falls. That is the sitting that matters.
- 4
Do not invent a numerator
Pre-revenue, there is no revenue change to annualize. No S&M spend, there is no denominator that means anything. Do not plug in a “we will add $X next year” forecast so the spreadsheet prints a Magic Number. That is a model, not a measurement.
- 5
Say the S&M definition out loud. Keep channels honest.
Scale prefers excluding stock-based compensation from GAAP S&M. If you include it, say so and keep it consistent. A company-level Magic Number can still hide one expensive channel — that is what CAC payback is for, on a different page. Company cash versus net new ARR is burn multiple, also a different page. This sitting is S&M → incremental revenue.
What you leave with
The Magic Number tripwire (copy this)
If the sitting produced a ratio and no dated action, you did not finish. Fill the brackets. Leave nothing as “efficiency is fine,” “soon,” or “we’ll know it when ARR looks right.”
The fill-in contract
Product: [name]. Periods: [Q−1 start–end] → [Q start–end]. Hypothesis this number can falsify: [paid growth can pay for itself well enough to scale S&M]. Revenue_Q−1: [GAAP / subscription]. Revenue_Q: [same definition]. S&M_Q−1: [GAAP S&M, SBC excluded? yes/no]. Signal: [Magic Number = ((Revenue_Q − Revenue_Q−1) × 4) ÷ S&M_Q−1, and/or change vs last pair]. Threshold: [e.g. honor a miss if Magic Number is below 1x before we scale paid — Yibud template using Scale’s >1x compelling band, not First Round Level 4 pasted onto seed]. Window: books close [date], written before the first report. Action if miss: [scale S&M / hold / cut paid channels / keep testing organic]. Compare the next pair on the same definition. A Yibud score does not fire this line.
The “below 1x before we scale paid” line is Yibud’s suggested template for a scale-up decision, taken from Scale’s 2010 >1x compelling-investment band — not First Round’s Level 4 >1 pasted onto a twelve-person company, and not Scale Studio’s ~0.7 median treated as a personal target. Rewrite the threshold before you measure if you have a reason (a hold decision might honor Scale’s <0.5x floor instead). Do not rewrite it after.
Example tripwire (Yibud’s suggested template, not a law)
If, for Q2→Q3, Magic Number is below 1x when we close the books on 30 September → we do not scale paid acquisition in Q4; we hold S&M and keep only organic plus existing pipeline. Do not invent next-year revenue to create a numerator. Do not pair Q3 S&M with Q3 revenue and call it Magic Number without saying so.
A 1.2x on a single lucky quarter is still one quarter. A Yibud report score does not fire this tripwire.
The fork
When to use a Magic Number tripwire — and when not to
Magic Number is the wrong first instrument when there is no revenue yet, no S&M spend, or you are still running consumer ads-only tests to see if anyone clicks. It is the right instrument when subscription revenue is already moving and you are deciding whether paid growth can pay for itself.
Use it when you have two periods of revenue, a named S&M line, and a spend decision
You can name GAAP or subscription revenue for two consecutive quarters (or months with the same lag) and S&M for the earlier period. You are about to scale paid, hire quota-carrying reps, or tell yourself “growth covers it.” That is when a dated efficiency line earns its keep. Prefer two or three pairs so you can see direction, not one trophy quarter.
Do not start here when you are pre-revenue, have no S&M, or still need first money, reach, or a who-filter
No revenue yet? There is no change to annualize. Do not invent a numerator. No sales and marketing spend? The ratio does not mean what Scale meant. Consumer ads-only early tests that have not produced subscription revenue belong on reach or willingness-to-pay pages, not here. Months to recover CAC on one channel is a different instrument — that is the payback page. Company cash versus net new ARR is burn multiple. Still writing Stop / Pivot / Continue? Those are the decision contracts. This page supplies one GTM-efficiency number those contracts can later read. It does not replace them.
Worked example
Two B2B SaaS quarters you can copy (illustrative — fictional)
The quarters below are illustrative. Names, product, and counts are invented so you can see the arithmetic. It is not a study, not an industry benchmark, and not a Yibud report. Copy the method, not the numbers.
The promise, written before Q3 closes
Illustrative names: founder Maya Chen at Quotaflow, a pipeline-hygiene tool for mid-market B2B sales teams. Subscription revenue exists. S&M exists. The tempting trophy is a Q3 slide that shows revenue up and never mentions what Q2 S&M cost. The tripwire is written first, on 1 April: honor a miss if Q2→Q3 Magic Number is below 1x before we scale paid in Q4 — Yibud’s suggested template from Scale’s >1x compelling band, not First Round Level 4 pasted onto a fourteen-person company.
The inputs, kept honest
Q2 GAAP subscription revenue = $210,000. Q3 GAAP subscription revenue = $246,000. Change = $36,000. Annualized = $36,000 × 4 = $144,000. Q2 S&M, stock-based compensation excluded = $180,000. Magic Number = $144,000 ÷ $180,000 = 0.80. Last pair (Q1→Q2) on the same definition was 0.95. Headline revenue still rose. Magic Number slipped. Scale’s 2010 reading of 0.80: between 0.5x and 1x — possible path to success, capital-inefficient. Not <0.5x. Not >1x.
The tripwire, written 1 April
Signal: Q2→Q3 Magic Number and its change versus Q1→Q2. Threshold: honor a miss if the number is below 1x before we scale paid. Window: books close 30 September. Action if miss: do not scale paid acquisition in Q4; hold S&M; keep only organic plus existing pipeline. A Yibud score does not fire this line. The 1x bar is Yibud’s suggested template for a scale-up sitting, not Scale Studio’s ~0.7 median treated as a personal target, and not First Round’s Level 4 >1 treated as a seed law.
What a miss looks like — and what must not happen
Illustrative close: 0.80 is below 1x. 30 September is a miss on the bar they wrote. Hold paid. Do not pair Q3 S&M of $220,000 with Q3 revenue of $246,000, print an 89% S&M% as if this were a product company, and call the debate settled — that is the trap O’Driscoll wrote against. Do not forecast Q4 revenue to invent a friendlier numerator. Do not drop the lag so same-quarter S&M sits on same-quarter revenue without saying so. Do not treat First Round’s Level 3 >.75 as permission to scale when the tripwire you wrote was 1x. Keep Q3→Q4 on the same definition.
Write the tripwire before the first report. If the window closes and the pair misses the bar you wrote, honor the action. If it cleared the bar, continue to the next cheapest test — usually the next pair on the same definition, or a kill/pivot contract that now has a number to read. The method is the dated page, not the revenue headline.
Not the same page
Magic Number vs burn multiple, CAC payback, vanity metrics, WTP, Ellis, NPS, failure rates, market size, Yibud scores, and decision contracts
Several Yibud pages sit next to this one. Mixing them up turns a company cash ratio, a channel payback month, a waitlist, a recommend score, or a mid-band engine number into “sales efficiency works.”
Burn multiple — company cash vs net new ARR, not this S&M lag ratio
That page asks how much company cash you burned, in a period, per dollar of net new ARR (Net Burn ÷ Net New ARR). This page asks how efficiently S&M spend turned into incremental subscription revenue, often with a one-period lag. A 2x burn multiple does not tell you last quarter’s S&M paid for itself. A 0.8 Magic Number does not tell you the company is burning too much cash overall. Keep the instruments on separate pages.
Burn multiple for startups →CAC payback — months to recover a cohort’s acquisition cost, not this ratio
That page asks how many months of contribution recover fully-loaded CAC for a named cohort or channel. This page is a ratio: annualized revenue change divided by prior-period S&M. Payback can look fine on one cheap organic vintage while company-level Magic Number is below 0.5x. A 1.2 Magic Number does not tell you LinkedIn ads pay back. Keep the instruments on separate pages.
CAC payback for startups →Vanity metrics — hygiene class, not this efficiency tripwire
That page is the sorting hat: hits, cumulative signups, and waitlist size feel like progress and do not tell you what to do next. This page is one specific actionable efficiency number. A pretty Magic Number chart with no tripwire can still be vanity. A waitlist is not incremental GAAP revenue.
Vanity metrics for startups →Willingness to pay — first money on a deal, not S&M versus incremental revenue
That page is a deposit, pre-order, paid concierge, or priced checkout as proof that money moved once. Magic Number needs two periods of recognized revenue and a named S&M line. A paid first month with a 0.4 Magic Number can still miss the tripwire you wrote.
Willingness-to-pay test →Sean Ellis PMF survey — disappointment among current users
That page’s signal is the percent of recent real users who would be very disappointed if the product disappeared. Scale’s >1x band is a sales-efficiency sitting, not Ellis’s question. Do not treat “very disappointed” as a Magic Number, and do not treat a 1.2 Magic Number as Ellis’s bar.
Product-market fit survey →NPS — one recommend-intent score
That page is stated recommendation intent among people who already used you. A high NPS does not raise Magic Number. A 1.2 Magic Number does not mean people would recommend you. Keep the instruments on separate pages.
NPS for early-stage startups →Startup failure rate — population frequencies, not the math
That page is what the failure data says at population level — BLS establishment survival, venture-backed “failure” as reported, and why a base rate is not your fate. This page teaches one sales-efficiency instrument those tables do not compute. It does not invent a “percent of startups that die from a low Magic Number.”
What percentage of startups fail →Market sizing — TAM/SAM/SOM, not sales efficiency
That page names buyers you can reach and a revenue story. A large SOM does not make a 0.4 Magic Number healthy. A 1.2 Magic Number does not size a market. Do not file a TAM slide under Magic Number.
Startup market sizing →Yibud scores — not Magic Number, and not a success prediction
The validation-score and score-calculator pages explain Startup MRI numbers from a deterministic rule engine on a one-line idea plus five questions. Those scores point at the weakest assumption to test next. They are not Magic Number. They are not burn multiple. They are not CAC payback. Do not read a mid-band monetization score as “sales efficiency works,” and do not read a 1.2 Magic Number as a Yibud GO.
Kill, pivot, critical assumption, decision — contracts that can read this number
Those pages write Stop, rewrite one dimension, name the one claim that would kill the idea if false, or decide after evidence. This page can supply the GTM-efficiency instrument those contracts later read: a dated Magic Number against a bar you wrote first. A revenue headline with no lagged S&M denominator cannot fire a kill line honestly.
Where Yibud fits
Neither Magic Number nor a Yibud score predicts success
Yibud is a free, no-signup startup idea validator. Scores come from a deterministic rule engine, not from a language model guessing success. Optional AI text, when it is used, only polishes prose. It does not invent the number. A Startup MRI report can name a weak monetization or distribution assumption, then a Day-7 Continue / Refine / Re-test / Stop signal. The score is a flashlight on the weakest assumption to test next — not Magic Number, not burn multiple, not CAC payback, not a forecast. Magic Number work sits next to that assumption: write the tripwire, do not hope a rising revenue slide means paid growth can pay for itself. If you already have a report, start with the named assumption, not the overall score. Then run the two periods yourself. The method on this page stands alone if you never open the analyzer.
Analyze my idea →Common mistakes
What usually wastes an early efficiency week
Treating >1 as proof you will succeed
A Magic Number above 1x means that pair of quarters cleared Scale’s 2010 “compelling investment” band — or cleared a bar you wrote. It does not mean the startup will succeed. It is not Ellis’s very-disappointed question, not a deposit, and not a Yibud GO. Neither Magic Number nor a Yibud report score predicts success.
Computing the ratio before any revenue — and inventing a numerator
Pre-revenue, there is no revenue change to annualize. Plug in a forecast and you have a model, not a measurement. No S&M spend is a different empty sitting, not a license to divide by a planned hire plan. Do not print a fake Magic Number.
Ignoring the lag — pairing same-quarter S&M with same-quarter revenue without saying so
O’Driscoll’s whole point is the lag: prior-quarter S&M versus the change that shows up afterward. Same-period Gross or Net Sales Efficiency is a real Scale definition — Chang’s primer uses it — but it is not Magic Number. If you drop the lag, say you are looking at same-period SE. Do not relabel it.
Celebrating growth while Magic Number collapses
Headline subscription revenue can still rise while annualized change over prior S&M gets worse. That is the capital-inefficient path Scale put in the 0.5–1x band, or the “model not figured out” sitting below 0.5x. Direction of travel is the story, not the revenue trophy.
Pasting First Round’s Level 4 >1 onto a pre-seed consumer idea
Those Level marks are a sales-led B2B framework. First Round does not present them as a law for every consumer app. Level 1 names no Magic Number. Level 2’s .5–.75 line is written as ARR/CAC, which is not Scale’s GAAP formula. Write your own tripwire. Label Scale’s three bands as Scale’s, not a universal grade table.
Sources
Where these ideas come from
- Rory O’Driscoll / Scale Venture Partners, “Magic Number Math,” 20 April 2010 — Used for why S&M as a percent of current revenue misleads subscription companies; the correct relationship (prior-quarter S&M vs the change in revenue afterward); the formula (annualize quarter-over-quarter revenue change and divide by earlier-quarter S&M); the three bands (>1x compelling; <0.5x model not figured out; 0.5–1x capital-inefficient path to success and cash-flow breakeven); and the simplicity caveat plus GAAP comparability. This page does not invent further grade tiers.
- Dale Chang / Scale Venture Partners, “SaaS Metrics: A Primer on SaaS Sales Efficiency,” 8 September 2020 — Used for Gross Sales Efficiency (Gross New ARR ÷ same-period S&M), Net Sales Efficiency (Net New ARR ÷ same-period S&M), and Magic Number as the GAAP workaround (annualize Δ revenue, prior-quarter S&M) when ARR definitions vary; Scale Studio’s long-term median Magic Number around 0.7 among 1,000+ growth-stage SaaS/cloud businesses; above 1 rare and attractive; preference to exclude stock-based compensation from the S&M denominator; and stickiness after about $10M in sales. Labeled as Scale’s dataset, not a universal law.
- First Round Capital, “Levels of PMF,” 8 April 2024 — Used for the Efficiency dimension including magic number (with CAC, CAC payback, NRR, gross margin, burn multiple); Level 1 (no Magic Number named — N/A); Level 2 (“Magic Number” (ARR/CAC) in the .5 to .75 range); Level 3 (magic number >.75, CAC payback <18 months); and Level 4 (magic number >1, CAC payback <12 months). Scope: written for sales-led B2B. This page does not treat those marks as a universal law.
In one paragraph
Summary you can quote
The SaaS Magic Number estimates how efficiently sales and marketing spend turns into incremental subscription revenue. Scale / O’Driscoll (20 April 2010): Magic Number = [(Revenue_Q − Revenue_Q−1) × 4] ÷ S&M_Q−1; S&M% of current revenue misleads subscription companies because this quarter’s revenue is mostly the annuity from past selling; >1x compelling; <0.5x model not figured out; 0.5–1x may reach success and cash-flow breakeven in a capital-inefficient way; simple on purpose, comparable because it is GAAP. Scale / Chang (8 September 2020): Gross SE vs Net SE vs Magic Number; Scale Studio median around 0.7 among 1,000+ growth-stage SaaS/cloud; above 1 rare; prefer excluding SBC; SE often sticky after ~$10M sales. First Round (8 April 2024), for sales-led B2B: Efficiency includes magic number; L1 N/A; L2 .5–.75 as ARR/CAC; L3 >.75 and CAC payback <18 months; L4 >1 and CAC payback <12 months. Write signal + threshold + window + action before you measure. Prefer the trend. Matching the gate is a decision signal. Neither Magic Number nor a Yibud score predicts success.
FAQ
Questions founders actually ask
What is the SaaS Magic Number?
A sales-efficiency ratio. Scale’s classic formula: take the change in subscription (GAAP) revenue between two quarters, annualize it (×4), and divide by sales and marketing spend in the earlier quarter. Higher means S&M turned into incremental revenue more efficiently. It is an efficiency number, not a success score.
What is a good Magic Number for a SaaS startup?
This page does not publish a universal “good” grade table beyond the sources. Scale (20 April 2010): >1x compelling; <0.5x model not figured out; 0.5–1x capital-inefficient path. Scale Studio (8 September 2020), Scale’s dataset of 1,000+ growth-stage SaaS/cloud: long-term median around 0.7; above 1 rare. First Round’s sales-led B2B Levels: L1 N/A; L2 .5–.75 written as ARR/CAC; L3 >.75; L4 >1. Write your own tripwire before you measure.
How is Magic Number different from burn multiple and CAC payback?
Burn multiple is company-level Net Burn ÷ Net New ARR in a period — cash versus growth. CAC payback is how many months of contribution recover fully-loaded acquisition cost for a named cohort or channel. Magic Number is a ratio of annualized revenue change to prior-period S&M. They answer different decisions. Use burn multiple for the cash sitting, payback for the channel, this page for S&M → incremental revenue.
Can I compute Magic Number before I have revenue?
No. Pre-revenue, there is no revenue change to annualize, so the ratio does not compute. No S&M spend is a different empty sitting. Do not invent a forecast numerator so a spreadsheet prints a Magic Number. Still testing whether anyone will pay? Use the willingness-to-pay page first.
Is a Yibud score the same as Magic Number? Does it predict success?
No and no. Yibud scores come from a deterministic rule engine on your idea inputs. They point at the weakest assumption to test next. They are not Magic Number, not burn multiple, not CAC payback, and not a forecast. Neither a Magic Number pass nor a Yibud report score predicts success. You do not need an account to use this page.
Write the sales-efficiency tripwire before the next quarter closes
Yibud scores weak assumptions with a deterministic engine. You write signal, threshold, window, and action while you are still honest — then two quarters of Magic Number are a tripwire, not a revenue slide.
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