# Rule of 40 Calculator

URL: https://www.paydude.io/resources/tools/rule-of-40-calculator
Type: Free interactive calculator
Summary: Add growth rate to profit margin and check it against 40. See which combinations pass, and what each half would need to be.

The Rule of 40 refuses to let either half be judged alone. Fast growth funded by enormous losses fails it, and so does comfortable profitability with no growth.

## Summary

Growth rate plus profit margin should exceed 40. It explicitly permits losses — if growth is high enough. Which profit measure you use matters; be consistent. It is a benchmark for scaled companies, not early-stage ones.

## Combinations that all score 40

**The trade, made explicit**

| Growth | Profit margin | Score |
| --- | --- | --- |
| 100% | −60% | 40 |
| 60% | −20% | 40 |
| 40% | 0% | 40 |
| 20% | 20% | 40 |
| 10% | 30% | 40 |

Every row is equally acceptable by the rule. That is the point: it prices the trade between growth and profitability rather than pretending one is always right.

## Which profit number to use

This is genuinely contested. EBITDA margin is the most common in public comparables. Free cash flow margin is the most honest, because it captures working capital and capitalised costs. Operating margin sits between them.

> **Pick one and keep it:** Switching profit measures between periods makes the score meaningless as a trend, and it is a well-worn way to make a bad quarter look acceptable. Whichever you choose, state it and stay with it.

## When it does not apply

- **Very early stage.** A company growing 300% from a small base scores absurdly well while proving nothing.
- **Pre-revenue or pre-product-market-fit.** There is no meaningful growth rate to measure.
- **Bootstrapped businesses by choice.** A profitable company growing 15% at a 30% margin passes, but the rule was built to evaluate venture-scale trade-offs.

It is most useful from roughly $10M ARR upward, where both halves are stable enough for the sum to mean something.

**Margin is the half you can move fastest** Payment fees come straight out of it. — [See pricing](https://www.paydude.io/pricing)

## Frequently asked questions

### What is the Rule of 40?

Year-over-year revenue growth rate plus profit margin should be at least 40. A company growing 60% with a −20% margin scores 40, as does one growing 20% at a 20% margin. It prices the trade-off rather than favouring one side.

### Which profit margin should I use?

EBITDA margin is most common in public comparables; free cash flow margin is the most honest. What matters more than the choice is consistency — switching between them makes the trend meaningless.

### Does the Rule of 40 apply to early-stage startups?

Not usefully. A company growing 300% from a tiny base scores extraordinarily well while proving very little. It becomes meaningful from roughly $10M ARR, where both inputs are stable.

### Is a score above 40 always better?

Generally yes, though a very high score achieved through profitability alone can signal underinvestment in growth. Investors typically prefer 40 reached with strong growth over 40 reached with high margins and stagnation.