SaaS Magic Number Calculator
Calculate the SaaS Magic Number — net new ARR divided by previous-quarter sales & marketing spend, the sales-efficiency ratio coined at Scale Venture Partners. Above 1.0 means scale faster; below 0.5 means fix the funnel before adding budget.
SaaS Magic Number Calculator
Net new ARR this quarter
Sales & marketing spend
Sensitivity — Magic Number at different S&M spend levels
Reference points from Scale Venture Partners
How to use the SaaS Magic Number Calculator
Calculate true net new ARR for the quarter
Net new ARR = ending ARR − starting ARR for the quarter. It already nets new logos and expansion against churn and contraction, so do not subtract churn again. For example, if ARR went from $20M to $22M, net new ARR for the quarter is $2M. If you only have MRR, multiply by 12 to get ARR. Use booked, not billed — Magic Number is a sales-efficiency metric, not a cash metric.
Use the previous quarter's S&M spend
This is the part founders get wrong most often. The convention deliberately uses the prior quarter's S&M spend because sales and marketing dollars typically take one to two quarters to convert into booked ARR — a paid ad today produces a demo next month and a closed deal the month after that. Using the same quarter's S&M understates efficiency for fast-growing businesses and overstates it for businesses that just slashed budgets.
Include fully-loaded S&M, not just ad spend
Fully-loaded S&M = all sales salaries and commissions (AEs, BDRs, SEs, leadership), marketing headcount, paid ad spend, content production, demo and sales-tool subscriptions, events, allocated overhead. Founders who count only paid ads understate S&M and produce a Magic Number that looks impossibly good. Investors will always recompute with the full number — use the honest version first.
Read against the four bands and the sensitivity table
Scale Venture's published thresholds are three: above 1.0 is "a compelling business investment", 0.5–1.0 will probably reach break-even "but only in a relatively capital-inefficient way", and below 0.5 "still has not figured out its model". This tool splits the middle band at 0.75 as an added caution line. Then look at the sensitivity table: it shows what happens to your Magic Number if you push S&M up 25%, 50%, or 100%. That tells you how much room you have to scale before crossing into a worse band.
SaaS Magic Number — the metric that tells you whether to step on the gas
The SaaS Magic Number comes from Scale Venture Partners. By the firm's own account, partner Rory O'Driscoll was evaluating Omniture in the mid-2000s, saw that it generated more than two dollars of first-year revenue for every dollar spent on its go-to-market engine, and exclaimed "It's magic!" The formula that followed is brutally simple: take the change in subscription revenue between two quarters, annualise it (multiply by four), and divide by the sales and marketing spend of the earlier quarter. Because net new ARR is already an annual figure, the ARR version of the formula is simply net new ARR ÷ prior-quarter S&M — which is what this calculator computes when the annualise box is left off. Above 1.0, every dollar of S&M last quarter generated more than a dollar of new recurring revenue this quarter — pour fuel on the fire. Below 0.5, the model has not been figured out yet and more fuel will not fix it.
Why the one-quarter S&M lag matters
The lag is what makes the Magic Number honest. SaaS sales cycles are not instantaneous. A demand-generation dollar spent in January funds a webinar in February, which produces a demo in March, which closes as a contract in April. Using this quarter's S&M against this quarter's ARR would credit January spend with March deals it never touched, and starve recently-spent budget of the bookings still in flight. The previous-quarter convention approximates the real conversion lag without requiring the company to build a cohorted pipeline model. For most SaaS businesses with sales cycles under 90 days the one-quarter lag is close enough; for enterprise SaaS with longer cycles, some operators use a two-quarter lag instead.
Variants of the formula — and the two mistakes to avoid
Several "Magic Number" formulas circulate in SaaS finance, and they are not identical. Scale Venture's original uses the annualised change in quarterly subscription revenue ÷ prior-quarter S&M; the common ARR version uses net new ARR ÷ prior-quarter S&M, which is the same thing expressed in ARR terms. Some practitioners use current-quarter rather than prior-quarter S&M, and some use gross new ARR (ignoring churn), which flatters the ratio by crediting S&M for revenue you would have kept anyway. Two mistakes matter more than the choice of variant. First, do not annualise twice: net new ARR is already annual, so multiplying it by four overstates the ratio fourfold. Second, the payback shorthand: with Magic Number M defined on ARR, the prior quarter's S&M is 1 ÷ M years of new recurring revenue, so CAC payback is roughly 12 ÷ (M × gross margin) months — 16 months at M = 1.0 and a 75% margin, not four. The "4 ÷ M" figure this tool displays is that payback expressed in quarters at a 100% gross margin.
A Magic Number above 1 says: every dollar you spend on sales today generates more than a dollar of recurring revenue tomorrow. Raise more, spend more.
The six-quarter compression pattern
One of the unspoken truths of the Magic Number is that it tends to compress as a company scales. Scale Venture's own analysis of a decade of private and public SaaS data describes the pattern: the easiest customers are acquired first, the addressable market saturates, and S&M effort shifts to harder-to-reach buyers, so the same dollar buys less new revenue over time. The right reaction is not panic but planning. Companies that recognise the pattern raise while the Magic Number is high, deploy deliberately, and budget for a glide path down. Companies that miss it keep spending at the old efficiency assumption and burn through their runway.
The ASEAN angle — why regional SaaS Magic Numbers run lower
Singapore and Southeast Asian SaaS businesses face a structural Magic Number headwind. With smaller addressable markets, less product-led pull and longer outbound sales cycles, every dollar of S&M tends to extract less new ARR than it would for a US peer selling into a far larger home market — while talent and advertising costs are set globally. The compensation strategies are recognisable: move up-market to higher-ARPC segments earlier, lean on product-led acquisition to compress CAC, and cut underperforming channels from year one. Founders who can show the ratio's trajectory and the levers they are pulling on it raise more easily than those who present a single quarter's number.
Scale Venture's ratio: annualised new revenue over the prior quarter's S&M
The Magic Number was coined at Scale Venture Partners: evaluating Omniture in the mid-2000s, partner Rory O'Driscoll saw more than $2 of first-year revenue per $1 of go-to-market spend and called it "magic".
The convention uses the previous quarter's S&M spend, not the current quarter's — because S&M dollars take 1–2 quarters to convert into booked ARR. Using same-quarter spend understates efficiency for growing businesses.
CAC payback is roughly 12 ÷ (Magic Number × gross margin) months: a Magic Number of 1.0 at a 75% margin implies about 16 months, 2.0 about 8. The "4 ÷ Magic" shorthand gives the payback in quarters at a 100% margin.
Do not annualise twice. Scale's formula multiplies a change in quarterly revenue by four; net new ARR is already annual. Multiplying ARR by four overstates the ratio fourfold — the most common spreadsheet error with this metric.
The Magic Number tends to compress over time as the easiest customers are acquired and the addressable market saturates — Scale Venture's decade-long dataset of private and public SaaS shows the pattern repeatedly.
Scale Venture's three thresholds: above 1.0 is "a compelling business investment"; 0.5–1.0 gets to break-even "only in a relatively capital-inefficient way"; below 0.5 "still has not figured out its model".
Variants differ in whether they lag S&M by a quarter and whether they net out churn. Using gross new ARR (ignoring churn) flatters the ratio; the lagged, net version computed here is the conservative one.
Investors love the Magic Number because it is a single forward-looking gauge — it answers "will the next dollar of capital work?" in a way that growth rate alone cannot. Boards use it to decide whether to approve incremental headcount and budget.
ASEAN SaaS Magic Numbers tend to run lower than US peers' — smaller home markets, longer outbound cycles and less product-led pull mean the same S&M dollar buys less new ARR, while talent and ad costs are set globally.
A Magic Number below 0.5 is treated by investors not as "needs more growth capital" but as "needs a turnaround" — a fundamentally different conversation. Fix the funnel before raising more, or watch the next round's valuation reset.
Frequently Asked Questions
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Above 1.0 is "scale-worthy" — every dollar of S&M produces more than a dollar of new ARR. Between 0.75 and 1.0 is "healthy, keep pace." Between 0.5 and 0.75 is "cautious — audit the funnel before adding spend." Below 0.5 is a serious efficiency problem requiring pull-back, not more capital. Scale Venture's own published thresholds are the 1.0 and 0.5 lines; the 0.75 line is this tool's added caution band.
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Because S&M dollars take time to convert. A paid ad in January funds a demo in February and a closed deal in March. Using same-quarter S&M would credit recent spend with bookings still in flight and undercount the ARR that current spend will eventually produce. The one-quarter lag is built into Scale Venture's original definition — S&M "for the earlier of the two quarters" — and it remains the standard. Enterprise SaaS with longer sales cycles sometimes uses a two-quarter lag instead.
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Only if your numerator is a change in quarterly revenue. Scale Venture's original formula takes the difference between two quarters' subscription revenue and multiplies by four to turn a quarterly figure into an annual run-rate. Net new ARR is already an annual run-rate, so it must not be multiplied again — doing so overstates the Magic Number fourfold. That is why the annualise box is off by default: tick it only when you have entered annualised — directionally fine but not comparable to industry benchmarks, which are universally annualised.
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If M is the Magic Number on an ARR basis, the prior quarter's S&M equals 1 ÷ M years of new ARR, so the new customers repay it in 12 ÷ M months of revenue — or 12 ÷ (M × gross margin) months of gross profit. At a 75% margin, M = 1.0 implies about 16 months, M = 2.0 about 8 and M = 0.5 about 32. The "implied payback" cell above shows 4 ÷ M, which is the payback in quarters at a 100% margin; multiply it by 3 and divide by your gross margin to get months. Lower gross margins stretch the payback further — at 60% gross margin, divide 4 by your Magic Number and then multiply by 1.25 for a closer estimate.
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Scale Venture's original formula annualises the change in quarterly subscription revenue and divides by the earlier quarter's S&M — equivalent to net new ARR ÷ prior-quarter S&M, the lagged version computed here. Other practitioners use current-quarter S&M (a lower number for a growing business) or gross new ARR that ignores churn (a higher, flattering number). The lagged, net version is the conservative one and what most investors expect to see.
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Fully-loaded S&M, always. Include all sales salaries and commissions (AEs, BDRs, SEs, leadership), marketing headcount, paid ads, content, sales tools, demo infrastructure, events, and allocated overhead. Founders who count only paid-ad spend understate S&M and produce Magic Numbers that look impossibly good. Investors will always recompute with the fully-loaded number — the flattering version only sets you up for a painful diligence conversation.
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Almost every SaaS sees Magic Number compression over six to ten quarters. The earliest customers are the easiest — closest fit, fastest decisions, lowest CAC. As you scale, you must reach further into the addressable market, persuade harder-to-convince buyers, and compete with more incumbents. S&M effort per new ARR dollar inevitably rises. The right reaction is to raise larger rounds while the Magic Number is high, deploy aggressively, and accept a glide path down toward the long-term median of about 0.7 that Scale Venture reports across its SaaS database.
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There is no published rule. Scale Venture's thresholds are the reference: above 1.0 has "proven to be a compelling business investment", and below 0.5 is a business that has not yet found its model. Investors generally want to see the ratio sustained over several consecutive quarters rather than a single strong one, and to understand which levers — pricing, channel mix, churn — produced it. Regional investors weigh the smaller-market headwind, but expect the founder to name it and show how it is being managed.
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Smaller addressable markets, less product-led pull, longer outbound sales cycles, and more fragmented buying processes mean every S&M dollar in Southeast Asia extracts less new ARR than its US equivalent. CAC is broadly comparable to US peers' because talent and ad costs are set globally, but the home market is a fraction of the size. Regional investors know this and read the ratio alongside its trajectory and components rather than against a US benchmark alone.
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No. All calculation happens entirely in your browser via JavaScript — no server call, no analytics on the inputs, nothing sent over the network. Open DevTools → Network and confirm: there is zero outbound traffic from the calculator while you type.
Method & sources
How it computes
Magic Number = (net new ARR this quarter, optionally × 4 when the input is a quarterly revenue change) ÷ previous quarter's sales & marketing spend. Breakeven S&M = the numerator (spend at which Magic = 1). Bands: ≥ 1.0 scale, 0.75–1.0 healthy, 0.5–0.75 cautious, < 0.5 problem (Scale Venture publishes the 1.0 and 0.5 lines; 0.75 is this tool's addition). The displayed 'implied payback' is 4 ÷ Magic, which is payback in quarters at a 100% gross margin.
What this tool implements
- Scale Venture Partners' definition: change in subscription revenue between two quarters, annualised (× 4), divided by S&M spend for the earlier quarter; thresholds > 1.0 compelling, 0.5–1.0 capital-inefficient, < 0.5 model not yet found
- Net new ARR is already annual — the annualise (× 4) option is off by default and applies only to a quarterly revenue change
- One-quarter S&M lag; fully-loaded S&M; net of churn
- Correct payback relation stated on page: months ≈ 12 ÷ (Magic × gross margin)
Sources
- Scale Venture Partners. Magic Number Math. https://www.scalevp.com/insights/magic-number-math/
- Scale Venture Partners. SaaS Metrics: A History of the Magic Number. https://www.scalevp.com/blog/saas-metrics-a-history-of-the-magic-…
What can make this go out of date
- none at runtime
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