From the team at Flowjam · Published July 2026

What the Rule of 40 actually is

The Rule of 40 is a shorthand investors use to judge whether a software company is balancing growth and profitability. The formula could not be simpler:

A company growing revenue 30% a year with a 12% margin scores 42 and passes. One growing 20% while burning at a -15% margin scores 5 and does not. The point is that neither number is good or bad on its own: hypergrowth funded by torching cash and slow growth with fat margins can both be fine, as long as the pair adds up. The rule forces the tradeoff into one honest number.

How to calculate it without fooling yourself

Two choices decide whether your score means anything.

1. Which growth rate

Use year-over-year revenue or ARR growth. Be consistent: compare the trailing twelve months to the prior twelve, not a cherry-picked good quarter annualized.

2. Which margin: FCF or EBITDA

This is where scores get gamed. Free-cash-flow margin is the stricter, more honest measure. EBITDA margin looks better because it adds back stock-based compensation and other non-cash charges, which for software can be enormous. The gap is real: on a free-cash-flow basis about 46% of public SaaS companies clear 40, but on EBITDA only about 15% do. Pick FCF if you want the number to be true rather than flattering.

What a good score looks like in 2026

Measure yourself against the market before you celebrate or panic.

Benchmarks: Aventis Advisors, Rule of 40 in SaaS 2026, across public and private B2B SaaS. Ranges vary by cohort; treat as goalposts.

Why investors care so much about one number

Because it predicts durable value, and it shows up directly in what your company is worth. A 10-point jump in your score can roughly double your revenue multiple, which is why it is one of the first things a growth investor screens for. Companies that consistently clear 40 raise on better terms and are far less likely to hit the wall where growth slows and there is no profitability to fall back on. Here is how the score maps to the multiple:

Illustrative ranges for growth-stage B2B SaaS; actual multiples swing with rates, retention, and market cycle. The direction, not the exact figure, is the point.

The Rule of 40 is also a quick test for whether growth is bought (unsustainable spend) or earned (efficient engine). A score of 45 built on 40% growth and a 5% margin tells a very different story to an investor than 45 built on 15% growth and a 30% margin: the first is a growth bet, the second is a profitable compounder. In diligence, expect the two halves to be pulled apart and stress-tested, so always read them separately, not just the sum.

The cheapest way to move your score

When you are below the line, founders reflexively try to grow faster. That is usually the expensive lever. The cheaper one is the margin side, and inside that, your cost to acquire a customer. Every dollar you shave off CAC and every week you cut from payback drops straight toward the margin without slowing the top line.

What the Rule of 40 hides

• It rewards a single quarter. A one-time cost cut can push you over 40 without a healthier business. Look at the trend, not one reading.
• EBITDA flattery. A great-looking EBITDA score can sit on top of real cash burn. Always sanity-check against free cash flow.
• AI cost creep. In 2026, rising compute and model costs quietly eat the margin side. A score held up by pure growth can mask a widening cash gap.
• It says nothing about retention. Two companies can both score 42 while one keeps customers and the other churns and replaces them. Pair it with net revenue retention.
• Stage blindness. A seed-stage company should not optimize for 40; early on, growth rightly outweighs margin. The rule earns its weight from roughly Series B onward.

Rule of 40: frequently asked questions

What is the Rule of 40?
The Rule of 40 says a healthy software company's revenue growth rate plus its profit margin should add up to at least 40%. It is a single number that balances the two things that pull against each other: growing fast and making money. A company growing 30% with a 15% margin scores 45 and passes; one growing 20% at a -10% margin scores 10 and does not.

How do you calculate the Rule of 40?
Add your year-over-year revenue (or ARR) growth rate to your profit margin. For example, 25% growth + 20% free-cash-flow margin = a score of 45. The two common margin choices are free-cash-flow margin and EBITDA margin; pick one and stay consistent, because they can produce very different scores.

What is a good Rule of 40 score in 2026?
40 or above is the passing bar and top-quartile SaaS companies clear 43%+. The median B2B SaaS company sits around 25%, so simply reaching 40 already puts you ahead of more than half the market.

Should I use EBITDA or free cash flow for the margin?
Free cash flow is the stricter, more honest choice in 2026. EBITDA can be inflated by stock-based compensation and other non-cash charges, which is why far more public companies pass on an FCF basis (~46%) than on EBITDA (~15%). If you want the number to mean something, use FCF margin.

Is the Rule of 40 still relevant with AI cost pressure?
Yes, but read it carefully. Rising AI and infrastructure costs squeeze the margin side, so a company can hit 40 by pure growth while quietly burning cash on compute. Always look at what is driving the score, not just the total.

What is the Rule of 40 vs the Rule of 50?
Same idea, higher bar. As efficiency expectations rose, some investors moved the target for elite companies to 50. For most SaaS, 40 is still the benchmark to clear first; 50 is where the best compound.

Related reading: LTV:CAC ratio explained · SaaS metrics dashboard template · how to track MRR in Stripe.