Financial & Cost Signals

Rule of 40

The SaaS health heuristic that revenue growth rate plus profit margin should exceed 40% — a one-number test of whether growth is worth its cost.

Origin: Popularized in venture-capital writing in the mid-2010s, notably Brad Feld's "The Rule of 40% for a Healthy SaaS Company" (2015).

Definition

The Rule of 40 says a healthy software company's revenue growth rate and profit margin (typically free-cash-flow or EBITDA margin) should sum to at least 40. It formalizes the growth-profitability trade: growing 60% while burning a -20% margin passes; growing 20% at break-even does not. The heuristic spread through venture and growth-equity circles in the mid-2010s, popularized in essays by investors including Brad Feld (2015).

Its usefulness is comparative discipline: it puts a fast-growing money-loser and a slow-growing cash generator on one scale, which is how investors — and therefore boards — actually think about software businesses at scale. Its limits are equally known: it fits scaled companies better than early-stage ones, and it is a heuristic, not a law.

For competitive analysis of public rivals, the inputs are in the filings, and a competitor's Rule-of-40 trajectory frames their strategic room: a company sliding below the line faces investor pressure toward margin — predicting price increases, hiring slowdowns, and reduced product investment before they are announced.

Why it matters for competitive intelligence

A public rival's position against the Rule of 40 predicts the pressure they are under — and pressured companies make forced moves you can anticipate rather than react to.

How Rivalize helps

For public competitors, Rivalize pairs filing-derived facts with observed behaviour — pricing moves, hiring pace — so you can see a rival's efficiency pressure translating into market action.

Related terms

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Sources

  1. Brad Feld, "The Rule of 40% for a Healthy SaaS Company" (feld.com, 2015)

This definition is an educational summary of an established concept, written by the Rivalize team. It is not affiliated with, or endorsed by, the originators of the framework.