Rule of 40 calculator for SaaS

1. Enter revenue growth - your year-over-year growth rate as a percentage.
2. Enter profit margin - EBITDA or free cash flow margin (can be negative).
3. Read your score - growth + margin; 40 or above is healthy.
4. Add the Quick Ratio from your MRR movement for a second health check.
5. Act on the weaker lever - push growth or margin depending on what's dragging the score.

The Rule of 40 is popular with investors because it captures, in a single number, the central tension every SaaS faces: you can buy growth by spending more, or improve margin by spending less, but doing both well is hard. A company can hit 40 in very different ways - 40% growth at breakeven, or 10% growth at 30% margin - and the rule treats them as comparably healthy. What it penalizes is the dangerous middle: modest growth funded by heavy losses. Since the 2022-2026 shift toward capital efficiency, investors increasingly prefer companies that hit 40 with positive margin rather than pure burn-fueled growth, so the quality of the 40 matters as much as the number.

The Rule of 40 and the SaaS Quick Ratio answer different questions, and they're most powerful together. The Rule of 40 tells you whether your growth-and-profit balance is sustainable; the Quick Ratio tells you whether that growth is efficient or quietly undermined by churn. A company can pass the Rule of 40 on strong new sales while a weak Quick Ratio reveals it's losing nearly as much as it adds - a leak that will eventually drag the Rule of 40 down too. Checking both gives you an early warning the single metric would miss.

• If margin is the problem: reduce CAC, cut inefficient spend, raise prices, and improve gross margin.
• If growth is the problem: sharpen acquisition, add expansion revenue, and cut churn so net new MRR climbs.
• Protect retention. Expansion and low churn lift both growth and margin at once - the most efficient way to raise the score.