SaaS Magic Number Calculator
See how efficiently your sales and marketing spend converts into new revenue — the number investors use to decide whether to fund more growth spend.
Quarterly revenue & spend
Magic Number
1.00
= (Curr Q Rev − Prev Q Rev) × 4 ÷ Prev Q S&M Spend
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Last updated: August 5, 2026 · Reviewed by the DoCalc team
What Is the SaaS Magic Number?
The SaaS Magic Number measures how efficiently sales and marketing spend converts into new revenue — specifically, how much annualized revenue growth a company generated for every dollar spent on sales and marketing in the prior quarter. It's one of the most widely used efficiency metrics among growth-stage SaaS investors, because it directly informs a very practical question: is it a good idea to spend more on sales and marketing right now, or not yet?
Unlike CAC, which requires a customer count and measures cost per customer, the Magic Number works purely off revenue and spend at the company level — no customer-count data needed — which makes it easy to calculate from a standard P&L and quick to update every quarter.
The Formula
The quarter-over-quarter revenue increase is multiplied by 4 to annualize it, then divided by the previous quarter's sales and marketing spend — not the current quarter's. That lag is intentional: it typically takes time for S&M spend to convert into signed, revenue-generating customers, so comparing this quarter's revenue growth against last quarter's spend more accurately captures the return on that investment.
How Magic Number Works
A Magic Number above 1.0 means the company generated more than a dollar of annualized new revenue for every dollar of prior-quarter S&M spend — a strong signal that the growth engine is working efficiently, and that scaling S&M spend further is likely to pay off. A Magic Number well below 1.0 suggests the opposite: money spent on sales and marketing isn't converting efficiently into new revenue yet, and pouring more spend into the same engine before fixing the underlying efficiency problem often makes things worse, not better.
The metric is deliberately blunt and company-wide — it doesn't distinguish between spend on new-customer acquisition versus spend on retention/expansion motions, and it can be distorted by one-time spend spikes (a big conference sponsorship, a major campaign) that don't reflect steady-state efficiency. For that reason, most operators look at Magic Number as a trend across several quarters rather than reacting to any single quarter's number in isolation.
Worked Example
A company had $500,000 in revenue last quarter and $550,000 this quarter, having spent $200,000 on sales and marketing last quarter:
A Magic Number of 1.00 sits right at the boundary between "good" and "excellent" — this company generated a dollar of annualized new revenue for every dollar spent on sales and marketing the prior quarter, a strong efficiency signal that typically supports investing more in growth spend.
Magic Number Benchmarks
| Magic Number | What it signals |
|---|---|
| Below 0.75 | Inefficient — fix the growth engine before scaling spend |
| 0.75-1.0 | Good efficiency |
| 1.0+ | Excellent — efficient to invest more in sales and marketing |
Pros and Cons
Pros: a fast, P&L-level signal of sales and marketing efficiency; doesn't require customer-count data; directly informs the decision of whether to scale growth spend.
Cons: can be distorted by one-time or lumpy spend in a given quarter; doesn't distinguish new-customer spend from expansion/retention spend; a single quarter's number can be noisy and is best read as a trend.
Who Should — and Shouldn't — Use This Calculator
Use it if you want a fast, company-wide read on whether sales and marketing spend is converting efficiently into revenue growth — useful before deciding to scale S&M budget.
Skip or adjust for it if you need a per-customer efficiency number instead of a company-wide one — that's what the CAC Calculator measures.
Common Mistakes to Avoid
The most common mistake is using the current quarter's S&M spend instead of the prior quarter's, which ignores the natural lag between spend and revenue conversion and produces an artificially low (or misleading) number. A second mistake is reacting to a single volatile quarter rather than tracking the trend over several quarters. A third is comparing Magic Number across companies with very different sales cycle lengths — a company with a 12-month enterprise sales cycle will structurally show a lower Magic Number in any given quarter than a company with a two-week self-serve motion, even at similar underlying efficiency.
Worth knowing: Magic Number and CAC answer related but different questions — Magic Number is a company-wide efficiency ratio, while CAC is a per-customer cost figure. Strong performance on one doesn't guarantee strong performance on the other if customer count and deal size shift independently.
Expert Recommendation
Track Magic Number over at least 3-4 consecutive quarters before drawing conclusions, and exclude known one-time spend spikes from the S&M figure when possible, since they distort a single quarter's number without reflecting real steady-state efficiency.
Frequently Asked Questions
What is the SaaS Magic Number?
The SaaS Magic Number measures sales and marketing efficiency: how much annualized new revenue you generate for every dollar spent on sales and marketing in the prior quarter.
What's a good Magic Number?
Above 1.0 is considered excellent, signaling it's efficient to invest more in sales and marketing. 0.75 to 1.0 is good. Below 0.75 suggests fixing efficiency before scaling spend further.
Why use the previous quarter's S&M spend?
Because there's typically a lag between spending on sales and marketing and that spend converting into signed, revenue-generating customers — using the prior quarter's spend against the current quarter's revenue growth accounts for that delay.
Why multiply the net new revenue by 4?
Multiplying the quarter-over-quarter revenue increase by 4 annualizes it, putting it on the same yearly basis conventionally used for comparing SaaS efficiency metrics.
What counts as S&M spend?
All fully-loaded sales and marketing costs for the period — salaries, commissions, advertising spend, marketing tools, and related overhead — everything invested in acquiring and closing new revenue.
How is Magic Number different from CAC?
CAC measures cost per individual customer acquired; Magic Number measures overall revenue efficiency of the entire S&M investment at the company level, without needing a customer count.
Should Magic Number be calculated every quarter?
Yes — it's inherently a quarter-over-quarter metric, and tracking it every quarter reveals whether sales and marketing efficiency is improving, declining, or holding steady as spend scales.
Conclusion
Magic Number is the fastest available signal for one of the most important growth decisions a SaaS company makes: whether to pour more money into sales and marketing right now, or fix efficiency first. Read as a multi-quarter trend, it's one of the clearest calls investors and operators make together.