Rule of 40

What Is the Rule of 40?

The Rule of 40 is a SaaS benchmark holding that a software company's revenue growth rate plus its profit margin should equal or exceed 40. It treats growth and profitability as one budget: a company can spend margin to buy growth or bank margin and grow slower, but the two together must clear the bar.

How the Rule of 40 Works

The Rule of 40 exists because judging a software company on growth alone or margin alone produces the wrong answer. A company growing 100 percent while burning enormous sums might be compounding value or buying revenue at a loss. One posting 40 percent margins on 5 percent growth is profitable and going nowhere. Growth rate plus profit margin in one score forces both facts into view.

The threshold of 40 is a convention, not a law, but it has held up as a rough dividing line between businesses that create value as they scale and businesses that consume it. Companies above 40 generally trade at higher revenue multiples than those below, and the gap widens above 60.

The score matters most as a trend. A company moving from 22 to 31 to 39 over three years shows operating leverage: fixed costs spread across a larger base while growth moderates. One sliding from 45 to 30 is usually buying growth that no longer pays for itself.

How to Calculate the Rule of 40

The calculation is deliberately simple: take year over year revenue growth as a percentage and add the profit margin. Losses enter as a negative number.

Formula: Rule of 40 Score = Revenue Growth Rate + Profit Margin

A company growing 60 percent with a negative 20 percent free cash flow margin scores 60 plus negative 20, or exactly 40. One growing 20 percent at a 25 percent EBITDA margin scores 45. One growing 10 percent at a 10 percent margin scores 20 and is failing on both dimensions at once.

Measure growth on recurring revenue, not total revenue: a large one time services quarter can flatter the number for a year and then reverse it.

The Rule of 40 in Plain English

Fast growth buys permission to lose money. Slow growth does not. Growing 50 percent a year, investors will tolerate losing 10 percent of revenue. Growing 8 percent, you had better be earning 32 percent. Add the two numbers: above 40 and the business is holding up its end.

Which Margin Belongs in the Rule of 40

This is where comparisons quietly break. Three margins are in common use and they do not agree.

EBITDA margin is the most widely quoted and the most generous, excluding interest, taxes, depreciation, and often stock based compensation. Operating margin is stricter. Free cash flow margin is the most honest, capturing working capital, capitalized software, and the timing of collections.

A company with annual upfront billing can post a free cash flow margin well above its EBITDA margin, while one collecting monthly shows the reverse. Confirm both companies use the same definition before drawing a conclusion.

The Rule of 40, Capital Efficiency, and Burn Multiple

The Rule of 40 measures the outcome. Capital efficiency measures the process, and burn multiple is the cleanest view of it.

Formula: Burn Multiple = Net Burn / Net New ARR

A company burning $12,000,000 to add $8,000,000 of net new ARR has a burn multiple of 1.5x: every dollar of new recurring revenue cost a dollar fifty of cash. Under 1x is excellent, 1x to 2x workable, above 3x usually a go-to-market problem rather than a spending problem.

The two answer different questions. The Rule of 40 asks whether the business as a whole is balanced. Burn multiple asks whether the growth being bought is worth the price. A company can pass the Rule of 40 on a mature installed base while its incremental growth is deeply inefficient.

Limitations of the Rule of 40

The Rule of 40 is a heuristic, and it fails at the edges. Early stage companies with small revenue bases produce wild percentages that mean very little. Very large companies find high growth structurally hard, so a mature business at 35 may be healthier than a smaller one at 45.

It also ignores gross margin quality, net revenue retention, and acquisition efficiency, all of which change what a given number means. Two companies scoring 45 are not equivalent if one holds 120 percent net revenue retention and the other 90 percent.

The Rule of 40 and the Closing Motion

Both terms in the Rule of 40 are affected by how a company closes. Discounting to win a deal permanently reduces the margin side of the score, and slow collection forces the company to fund growth with capital that carries a cost. Ratio built the Closing Motion for B2B technology scale ups around Propose, Close, Collect, Renew, with cash arriving at the moment of yes. With Ratio Trade, the buyer pays monthly or quarterly while the seller collects the full total contract value upfront, which turns a payment terms concession into a financing fee instead of a price cut. The fee is real and belongs in the margin calculation, but it is usually smaller and more predictable than the discount it replaces.

Common Questions About the Rule of 40

Does the Rule of 40 apply to early stage startups?

Not usefully below roughly $10,000,000 of ARR, where growth percentages are inflated by a small base and margin swings with a single hire. The Rule of 40 becomes meaningful once growth settles into a range a board can forecast.

Is a score above 40 always good?

Not if it comes from underinvestment. A company scoring 55 with 5 percent growth and a 50 percent margin is harvesting a market rather than expanding in one, and investors will value it as a cash generator, not a growth business. Read both components, not just the sum.

Which margin should be used for the Rule of 40?

Free cash flow margin is the most defensible because it reflects cash actually kept. EBITDA margin is the most common in benchmarking data. Either works as long as it is stated and applied consistently.

Key Takeaways

• The Rule of 40 adds revenue growth rate to profit margin and expects the total to reach 40 or better.
• Losses count as negative margin, so fast growth can carry a deficit and slow growth cannot.
• EBITDA margin, operating margin, and free cash flow margin give different scores, so always state which one you used.
• Pair the Rule of 40 with burn multiple, since the score can pass while incremental growth remains inefficient.
• The trend in the score matters more than any single quarter, because it reveals operating leverage.