The Rule of 40 is a rough benchmark for software companies stating that growth rate plus profit margin should add up to 40% or more, a way of judging whether a fast-growing but unprofitable company or a slower, profitable one is performing acceptably overall.
A company growing revenue 50% a year with a -10% margin scores 40, same as a company growing 20% with a 20% margin. Both are considered reasonably healthy under the rule, even though they look completely different on the income statement, which is exactly the point: it weighs growth and profitability together rather than favoring one in isolation.
The rule is a rough heuristic, not a precise formula, and it's most commonly applied to later-stage SaaS companies with meaningful revenue rather than early-stage startups still finding product-market fit. A pre-revenue or barely-revenue company scoring poorly on the Rule of 40 isn't a meaningful red flag the way it would be for a company several years into scaling.
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