Hong Life CalculatorsUnderstanding the SaaS magic number calculator — concept and principle
The SaaS magic number measures sales efficiency: how much new annualised revenue a subscription business gains for each unit of money it spent on sales and marketing in the previous quarter. Founders, CFOs and investors use it to decide whether to pour more money into growth or fix the go-to-market engine first. The calculator works with any currency.
How it is calculated
Magic number = (revenue this quarter − revenue last quarter) × 4 ÷ sales & marketing spend last quarter.
- The quarter-on-quarter revenue change shows how much recurring revenue was added.
- Multiplying by 4 annualises that quarterly increase.
- Dividing by the previous quarter's sales & marketing (S&M) spend relates the new revenue to the spending that most likely produced it, allowing for the lag between spending and closed deals.
The verdict follows the calculator's thresholds: 0.75 or more is "efficient — invest more", 0.5 to 0.75 is "OK", below 0.5 is "inefficient".
The principle
In a subscription business, one quarter's new customers keep paying in later quarters, so the useful question is how much annual revenue each unit of S&M spending creates. A magic number of 1 means one quarter's S&M spend creates the same amount in new annual revenue; at a healthy gross margin that spend pays itself back in roughly a year. The one-quarter lag reflects that sales cycles take time.
Worked example
- Revenue last quarter = 1,000,000 USD; this quarter = 1,150,000 USD.
- Increase = 150,000 USD; annualised = 150,000 × 4 = 600,000 USD.
- Previous quarter S&M = 500,000 USD.
- Magic number = 600,000 ÷ 500,000 = 1.2, verdict "efficient — invest more".
How to read the result
Above about 0.75, each extra unit of S&M money is turning into revenue quickly, which is a common signal to increase spending. Between 0.5 and 0.75, growth is acceptable but worth optimising. Below 0.5, look at pricing, churn, targeting and sales productivity before spending more. A very high value from a single quarter may be a one-off; look at several quarters.
Common mistakes
- Using total revenue that includes one-off services instead of recurring revenue.
- Ignoring churn: a flat revenue line can hide strong new sales offset by cancellations.
- Using the current quarter's S&M spend instead of the previous quarter's.
- Leaving out salaries, commissions or tools from S&M spend.
Frequently asked questions
Should I use revenue or ARR?
Either works if you are consistent. Some analysts use the change in quarterly recurring revenue; others use the change in ARR without the × 4.
Can the magic number be negative?
Yes, if revenue fell during the quarter. It means S&M spending did not even offset churn.
Is a magic number above 1.5 always good?
Not necessarily. It can mean you are under-investing in growth and could spend more while staying efficient.
Sources: Scale Venture Partners — the SaaS "magic number" sales-efficiency metric