Results are illustrative only and are not financial advice. This calculator provides estimates for educational purposes only. Past performance does not guarantee future results.
Results
Rule of 40 Score
45
Verdict
Passes
Revenue Growth
30%
FCF Margin
15%
Rule of 40 Calculator: Score Software Company Health in Seconds
Key Points
- Add revenue growth % and FCF margin % — a sum of 40 or above signals a healthy software business.
- Both inputs can be negative: slow growth + margin loss produces a below-zero score.
- FCF margin is the preferred measure; EBITDA margin is also used but can differ significantly.
- The benchmark applies to software companies above ~$15–20M ARR; early-stage hyper-growth inflates the score artificially.
The Rule of 40 formula
The Rule of 40 combines two percentages — revenue growth rate and a profitability margin — into a single score. A score of 40 or higher passes the benchmark; below 40 warrants scrutiny.
The formula works because it acknowledges the software growth trade-off: early-stage companies invest heavily in sales and infrastructure, accepting near-term losses in exchange for compounding recurring revenue. Neither high growth nor high margin alone is sufficient; the benchmark rewards a productive combination of both.
Score examples across different growth-margin profiles
Three common scenarios illustrate how the rule works across different stages and strategies.
- 30% growth / 15% FCF margin = 45 — balanced growth-profitability; passes comfortably.
- 50% growth / −15% FCF margin = 35 — fast growth but cash-intensive; fails the threshold.
- 5% growth / 38% FCF margin = 43 — mature, highly profitable; passes via margin alone.
FCF margin vs EBITDA margin
Free cash flow (FCF) margin — operating cash flow minus capital expenditures, divided by revenue — is the preferred measure in modern software analysis. It is difficult to engineer and reflects the actual cash the business generates after reinvestment.
EBITDA margin (earnings before interest, taxes, depreciation and amortization, divided by revenue) was more common in early SaaS literature. It ignores capital expenditures and can be flattered by high depreciation. For asset-light pure SaaS the two measures are usually close; for capital-intensive businesses they can diverge significantly.
When comparing Rule of 40 scores across sources, always confirm which profitability measure is being used.
The $15–20M ARR scale caveat
The Rule of 40 is less meaningful below roughly $15–20M in annual recurring revenue. At that scale, companies can post hyper-growth rates (200%, 300%) purely because of a tiny base — making the rule trivially easy to pass regardless of operational efficiency.
For early-stage companies, other metrics — net revenue retention, payback period, gross margin — are more informative. The Rule of 40 becomes increasingly relevant as a company crosses the $20–50M ARR threshold where growth is harder to sustain and margin discipline begins to matter.
Limitations of the Rule of 40
Like any single-number benchmark, the Rule of 40 has important limitations:
- Sector-specific — calibrated for software; produces misleading comparisons in other industries.
- One-dimensional — identical scores can represent very different business profiles (high-growth/loss-making vs low-growth/profitable).
- Gaming risk — companies can inflate the metric by delaying sales commissions, capitalizing R&D, or timing one-time cost cuts.
- Point-in-time — a single quarter can be distorted by seasonality or large one-time items; TTM or multi-year trends are more reliable.
Frequently asked questions
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