SaaS Magic Number Calculator
Calculate the SaaS magic number from new ARR and prior-quarter sales and marketing spend, with an implied CAC payback and an efficiency verdict.
How to use this tool
- Enter the net-new ARR added during the most recent quarter.
- Enter the total sales and marketing spend from the immediately prior quarter.
- Read the magic number, implied CAC payback, and efficiency verdict.
Measure how efficiently your sales and marketing spend turns into recurring revenue. Enter new ARR added this quarter and last quarter's S&M spend to get the magic number, implied CAC payback, and an efficiency verdict.
Formula
Magic number = New ARR added this quarter ÷ Prior-quarter S&M spend
Implied CAC payback (months) = 12 ÷ Magic number
The magic number measures how much new annual recurring revenue each dollar of sales and marketing buys, with a one-quarter lag (this quarter's growth is credited to last quarter's spend). A value of 1.0 means $1 of prior S&M produced $1 of new ARR — a 12-month payback.
How it works
The SaaS magic number gauges sales-and-marketing efficiency at the company level. It divides the new annual recurring revenue (ARR) added in a quarter by the sales and marketing spend of the previous quarter, on the logic that spend takes about a quarter to convert into revenue. The result is interpreted as ARR generated per dollar of S&M. Because the numerator is annualized revenue and the denominator is a single quarter's spend, the implied CAC payback is simply 12 divided by the magic number.
Common rules of thumb: below ~0.5 the go-to-market motion is inefficient and you should improve conversion before spending more; between ~0.75 and 1.0 is healthy; above 1.0 is excellent and usually argues for investing more aggressively. The metric is blunt — it ignores gross margin, mixes new and expansion revenue unless you isolate net-new, and is noisy quarter to quarter — so treat it as a directional efficiency signal rather than a precise figure. Use net-new ARR (gross new plus expansion minus churn) for the most honest reading, or gross-margin-adjusted ARR to be stricter.
Reviewed by the AbraCalc Business Desk. Educational estimate only, not investment advice; the thresholds are widely-used heuristics, not accounting standards.
Worked example
$2.0M new ARR on $2.5M prior S&M
- Magic number = 2,000,000 ÷ 2,500,000 = 0.80x.
- Implied CAC payback = 12 ÷ 0.80 = 15.00 months.
- 0.80 sits in the efficient zone (0.75–1.0).
Magic number = 0.80x, implied CAC payback = 15.00 months
Magic number, implied payback, and interpretation
| Magic number | Implied payback (months) | Interpretation |
|---|---|---|
| 0.25x | 48.00 | Inefficient |
| 0.50x | 24.00 | Below target |
| 0.75x | 16.00 | Good |
| 0.80x | 15.00 | Good |
| 1.00x | 12.00 | Good |
| 1.50x | 8.00 | Excellent |
| 2.00x | 6.00 | Excellent |
Key terms
- Magic number
- New ARR added in a quarter divided by the prior quarter's sales and marketing spend; a sales-efficiency ratio.
- ARR
- Annual recurring revenue — the annualized value of active recurring subscriptions.
- S&M spend
- Total sales and marketing cost, ideally fully loaded with salaries, commissions, and program spend.
- CAC payback
- Months needed to recover acquisition cost; here approximated as 12 divided by the magic number.
Frequently asked questions
- What is a good SaaS magic number?
- A magic number of 0.75 or higher is generally considered efficient, and above 1.0 is excellent and usually justifies investing more in growth. Below 0.5 suggests the go-to-market motion needs fixing before adding spend.
- Why use the prior quarter's spend?
- Sales and marketing investment typically takes about a quarter to convert into closed, recurring revenue. Crediting this quarter's new ARR to last quarter's spend captures that lag and avoids flattering fast-growing budgets.
- Should I use gross or net new ARR?
- Net-new ARR (new plus expansion minus churn) gives the most honest reading because it reflects what your go-to-market actually added. Using gross new ARR alone ignores churn and overstates efficiency.