How to calculate the Rule of 40
The Rule of 40 is a benchmark for software businesses that says growth rate plus profit margin should equal at least 40. It captures the core tension of scaling: you can grow fast and burn, or grow slower and profit, but the combination should clear the bar.
Short answer
Calculate the Rule of 40 by adding your revenue growth rate to your profit margin. If the sum is 40 or higher, the business is considered healthy. For example, 30 percent growth plus 15 percent profit margin equals 45, which passes. It balances the tradeoff between growing fast and being profitable.
Step by step
Pick your growth metric
Use year-over-year revenue or ARR growth rate as a percentage. Be consistent about which revenue basis you use.
Pick your profitability metric
Use a profit margin such as EBITDA margin or free cash flow margin as a percentage. Choose one and apply it consistently.
- Rule of 40 = growth rate percent + profit margin percent
- 40 or higher is considered healthy
- Use consistent revenue and margin definitions
Add them together
Sum the two percentages. A result of 40 or more suggests a healthy balance of growth and profitability.
Interpret the mix
A high-growth, low-margin company and a low-growth, high-margin company can both pass. The rule flexes with your stage.
Track the trend
Watch the number over time. A falling Rule of 40 signals growth is slowing without profitability rising to compensate.
How Ardovo helps
Because Ardovo ties revenue and financial data to one source of truth, growth and margin derive directly from live numbers, so Rook can report your Rule of 40 and its trend without a manual finance pull.
Frequently asked questions
What profit margin should I use for the Rule of 40?
EBITDA margin and free cash flow margin are both common. The key is consistency: pick one definition and apply it every period. Different margins produce different results, so document which you use when comparing to benchmarks or over time.
Can a company pass the Rule of 40 while unprofitable?
Yes, if growth is high enough. A company growing 50 percent with a negative 10 percent margin still sums to 40. The rule deliberately allows fast growth to offset thin or negative margins, and vice versa.
Is the Rule of 40 relevant for early-stage startups?
It is most meaningful for scaling software companies with real revenue. Very early startups often prioritize growth over the balance the rule measures, so it becomes a more useful health check as the business matures.