SaaS Magic Number Calculator
Sales & marketing efficiency.
Calculate the SaaS magic number from quarterly MRR growth and combined sales-and-marketing spend, given current and prior quarter MRR.
What this tool does
The SaaS magic number is a ratio that measures sales and marketing efficiency by comparing quarter-over-quarter monthly recurring revenue growth to the spending that drove it. The calculator takes your current and previous quarter MRR alongside previous quarter sales and marketing spend, then returns an annualised efficiency ratio. A result above 1 indicates that each unit of currency spent on sales and marketing generated more than one unit of MRR growth over the year. The metric relies on the assumption that current spending patterns remain consistent and doesn't account for seasonal variations, customer acquisition costs over time, or revenue retention rates. This calculation is for illustration only and reflects a snapshot of efficiency during a specific quarter.
Quick answer: with the default values, the result is 1.20 (Magic Number). Adjust the values below for your own figures.
Enter Values
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Formula Used
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Disclaimer
Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.
The SaaS Magic Number measures sales and marketing efficiency: how much new ARR each pound of previous-quarter S&M spend generated. Formula: (current MRR - previous MRR) × 12 ÷ previous-quarter S&M spend. Above 0.75 is generally read as efficient; 0.5-0.75 as a more cautious zone; below 0.5 as a sign of efficiency problems.
120k current MRR - 100k previous = 20k incremental MRR, or 240k new ARR. Against 200k of previous-quarter S&M spend, Magic Number = 1.2 — an efficient result, with each 1 of S&M producing 1.20 of new ARR within one quarter and the benefit compounding over future quarters. A reading above 1.0 is generally interpreted as efficient S&M spend with room to scale.
The one-quarter lag matters. S&M spent this quarter drives pipeline and wins next quarter, not this quarter. Measuring current quarter MRR against current quarter spend inflates the number; against previous quarter spend is the standard benchmark. Most public SaaS companies report Magic Number 0.6-1.2 in growth stages; mature SaaS 0.3-0.6.
A worked example
With the defaults: current quarter mrr of 120,000, previous quarter mrr of 100,000, previous quarter s&m spend of 200,000. The tool returns 1.20. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.
What moves the number most
The result responds to Current Quarter MRR, Previous Quarter MRR, and Previous Quarter S&M Spend. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.
The formula behind this
Magic Number = (MRR growth × 12) ÷ previous quarter S&M spend. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.
Using this as a check-in
Running this every three months shows a trend rather than a single snapshot. One reading shows where things stand; several over time show whether they are improving. The trend matters more than any individual reading.
What this doesn't capture
The result reflects only the inputs you provide and the assumptions built into the formula. It is a simplified model rather than a complete picture, and factors specific to your situation may matter just as much.
(£120,000 - £100,000) × 12 ÷ £200,000 = 1.20.
Inputs
| New ARR Added | $240,000.00 |
|---|---|
| S&M Spend | $200,000.00 |
| Efficiency Rating | Healthy |
| Current MRR Growth | $20,000.00 |
This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.
Sources & Methodology
Methodology
The calculator computes the Magic Number by measuring sales and marketing efficiency over a one-quarter period. It takes the difference between current-quarter monthly recurring revenue and previous-quarter monthly recurring revenue, multiplies that quarterly growth by 12 to annualize it, then divides the result by the previous quarter's sales and marketing spend. The output represents the revenue generated per unit of sales and marketing investment. The model assumes a linear, constant growth rate and does not account for seasonal variation, time lag between spending and revenue recognition, customer acquisition cost distribution, churn, or changes in pricing. Results reflect historical efficiency only and should not be interpreted as predictive of future performance.
References
Frequently Asked Questions
What's the interpretation?
Why the 1-quarter lag?
Magic Number vs CAC payback?
Does this work for early-stage?
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