Rule of 40

What it measures

The combined output of the two levers that drive enterprise value: top-line expansion and operating profitability. You add your revenue growth rate to your EBITDA margin and read the single percentage that results — 25% growth plus a 15% margin gives a Rule of 40 score of 40%. It deliberately treats a point of growth and a point of margin as interchangeable, so a company can clear the bar by leaning on either lever, but it says nothing about which one is carrying the score.

Why it matters

The Rule of 40 is the most compact scorecard the SaaS and scale-up world has for long-term value creation, because it captures the central trade-off every operator faces in one number: you can spend margin to buy growth, or harvest margin and accept slower growth, but you cannot ignore both. A score at or above 40% signals you are converting that trade-off into value on a sustainable path. Below 40% means something is leaking — growth has stalled, you are burning faster than the growth justifies, or both. Investors lean on it to decide whether a business is fundable; CFOs use it to frame strategy; boards use it as a fast proxy for whether the growth-versus-profitability balance is working.

How to read it

Read the score and its two components together — the headline number is meaningless without knowing which lever produced it. A company at 50% built from 10% growth and a 40% margin is mature and cash-generative but decelerating; a company at 50% built from 60% growth and a -10% margin is in hyper-growth and deliberately unprofitable. Both pass, and context decides which is healthier. A score at or above 40% is the conventional bar for a healthy SaaS or high-growth company; below 40% is a warning that you are either losing ground on growth or burning cash without the growth to justify it. Always decompose into growth and margin before you act, because the fix for a low score depends entirely on which side is dragging.

What good looks like

Watch-outs

• Dropping the sign on negative growth. If you are shrinking 5% year-over-year, that component is -5%, not +5% — a profitable company that is contracting is still bleeding score, and forgetting the sign flatters a failing business.
• Mixing time windows across the two components. Growth read month-over-month against a margin read on a trailing-twelve-month basis produces a meaningless sum. Compute both over the same window — T12M for strategic and investor reporting, month-over-month only for operational dashboards.
• Swapping in the wrong margin. The Rule of 40 is conventionally EBITDA margin; substituting net margin, free-cash-flow margin, or gross margin changes the score and breaks comparability with peers. Pick EBITDA margin and state it explicitly.
• Treating 40% as 'good enough.' Clearing the bar is the floor, not the goal — top SaaS companies target 50%+ and keep optimizing both levers. A business parked at exactly 40 for years is holding the line, not creating differentiated value.

Worked example