SaaS Magic Number Calculator — Leckie's 2008 Formula

Background.

The SaaS magic number measures how much annualised recurring revenue a company added for each dollar it spent on sales and marketing the previous quarter. The formula is quoted here exactly as the source that popularised it wrote it: Magic Number = (QRev[X] – QRev[X-1]) × 4 ÷ ExpSM[X-1], from Lars Leckie of Hummer Winblad, published as a guest post on Will Price's blog on 4 March 2008. Quarterly revenue rising from $11,000,000 to $12,500,000 on $6,000,000 of prior-quarter S&M gives ($1,500,000 × 4) ÷ $6,000,000 = 1.00.

Two design choices are worth understanding before you read the result. The spend is lagged by one quarter on the assumption that this quarter's revenue increase was bought by last quarter's selling effort — an assumption, not a measurement, and one that fits a ninety-day sales cycle better than a two-week or a two-year one. And the quarterly gain is multiplied by four to annualise it, which treats one quarter's increment as if it repeats for a year. Neither choice is wrong, but both are conventions, and the metric is only comparable between companies that apply them identically.

The thresholds everyone quotes come from that same 2008 post: below 0.75, "step back and look at your business"; above 0.75, "start pouring on the gas for growth because your business is primed to leverage spend into growth"; and "if you are anywhere above 1.5 call me immediately". Scale Venture Partners, whose Rory O'Driscoll coined the term after seeing Omniture generate more than $2 of first-year revenue per $1 of go-to-market spend, publishes a slightly different figure — "a Magic Number of 0.7x is a fairly healthy efficiency baseline". Both are recorded here; the banding uses 0.75 because it comes from the source that defines the formula.

The metric exists because public SaaS companies do not disclose internal ARR bookings, so an outside analyst has only GAAP revenue and reported S&M expense to work with. That is also its limitation: it is blind to churn composition, to whether the growth came from new logos or expansion, and to any one-off that moved reported revenue. A single large contract or a change in revenue recognition swings it far more than a change in sales productivity does. Do not confuse this page with the baseball magic number, which counts games needed to clinch a division.

What is saas magic number calculator?

The SaaS magic number is a sales-efficiency benchmark equal to the quarter-over-quarter increase in recurring revenue, multiplied by four to annualise it, divided by the sales and marketing expense of the preceding quarter. It answers the question "how much annual revenue did a dollar of go-to-market spend buy?" and is computable entirely from published quarterly financial statements, which is why it became the standard outside-in efficiency measure for public software companies. The term was coined at Scale Venture Partners and the formula was popularised by Lars Leckie of Hummer Winblad in a March 2008 post. It is not defined by any standard-setter, is not a GAAP or non-GAAP financial measure, and its two conventions — the one-quarter lag on spend and the fourfold annualisation — are choices rather than derivations. It is distinct from the bookings-based sales-efficiency ratios that operators compute internally, which use new ARR booked in the same period rather than the change in recognised revenue in the following one.

How to use this calculator.

1. 01Enter recurring revenue for the quarter just closed and for the quarter immediately before it. Use the same revenue line for both — mixing total revenue in one quarter with subscription revenue in the other makes the difference meaningless.
2. 02Enter total sales and marketing expense for the EARLIER of those two quarters. The lag is part of the formula; using the current quarter's spend produces a different metric.
3. 03Read the magic number against 0.75 and 1.5, the two levels the original post names, and remember that Scale Venture Partners publishes 0.7x as its own baseline.
4. 04Check the quarter-over-quarter growth figure alongside it. A high magic number on a tiny revenue base is a different result from the same number on a large one.
5. 05Before acting on a high reading, confirm the quarter contained no one-off contract, acquisition or revenue-recognition change — those move this metric far more than sales productivity does.

The formula.

Subtract the prior quarter's recurring revenue from the current quarter's to get the increment. Multiply by four to annualise it — the convention treats one quarter's gain as if it recurs for a full year. Divide by the sales and marketing expense of the prior quarter, not the current one, because the formula assumes a roughly one-quarter lag between spend and the revenue it produces. The result is dollars of annualised revenue per dollar of go-to-market spend. All arithmetic is carried at full decimal precision and rounded only at the return boundary, to two decimal places for the ratio and the growth percentage and two decimal places for currency. The banded reading is evaluated against the ROUNDED magic number, so a raw 0.7495 that displays as 0.75 is read in the 0.75 band rather than contradicting the number shown. Two inputs are guarded: prior-quarter S&M spend must be above zero because the formula divides by it, and prior-quarter revenue must be above zero because the metric measures an increase over an existing base and is not meaningful for a company's first revenue quarter. A revenue decline produces a negative magic number, which the calculator reports with its own reading rather than folding into the low band.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Leckie, L. (4 March 2008). "Magic Number for SaaS Companies." Guest post on Will Price's blog. Primary source for the formula quoted verbatim on this page — "Magic Number = (QRev[X] – Qrev[X-1])*4/ExpSM[X-1]" — and for the 0.75 and 1.5 thresholds, also quoted verbatim. Retrieved 29 July 2026; formula and thresholds verified against the live post.
2. [2]Scale Venture Partners. "SaaS Metrics: A History of the Magic Number." Independent second authority from the firm that originated the term: records Rory O'Driscoll's 2005 analysis of Omniture ("more than $2 in first-year revenue for every $1 invested in their go-to-market engine") and states "a Magic Number of 0.7x is a fairly healthy efficiency baseline" — a different baseline from Leckie's 0.75. Retrieved 29 July 2026.
3. [3]Jordan, J., Hariharan, A., Chen, F., & Kasireddy, P. (21 August 2015). "16 Startup Metrics." Andreessen Horowitz. Source for the definitional discipline on what counts as recurring revenue in the numerator. Retrieved 29 July 2026.
4. [4]U.S. Securities and Exchange Commission (30 January 2020). Release No. 33-10751, "Commission Guidance on Management's Discussion and Analysis of Financial Condition and Results of Operations." Relevant because the magic number is a non-standard operating metric: a registrant presenting it must disclose its definition and method of calculation. sec.gov returns HTTP 403 to automated fetchers; release identifiers verified independently.