Research Lab / Calculators
SaaS Rule of 40 Calculator: Two Paths to 40
Most Rule of 40 calculators give you a number and stop there. This one calculates the score, then shows the margin needed at your current growth and the growth needed at your current margin.
How to read your result
Your Rule of 40 score is the selected revenue growth rate plus the selected profitability margin. The total is useful, but the growth and margin components show how it is built.
The calculator also shows the margin needed if growth stays where it is and the growth needed if margin stays where it is. These are mathematical paths, not recommendations.
How to calculate the Rule of 40
Rule of 40 score = revenue growth rate + profitability margin
Growth rate = (current period value − prior period value) ÷ prior period value × 100
Profitability margin = selected profitability amount ÷ revenue × 100
Use the same metric for both periods and keep the selected growth basis, profitability basis, and period visible. Source: Brad Feld.
The two paths to 40
Margin needed at current growth = 40 − growth rate.
Growth needed at current margin = 40 − profitability margin.
For example, 28% growth with a 6% margin produces a score of 34. A company would need a 12% margin at 28% growth or 34% growth at a 6% margin.
What a Rule of 40 score can and cannot tell you
The Rule of 40 is a useful operating heuristic. It is not a valuation, a diligence report, or a company health diagnosis. A passing score can still conceal retention, customer concentration, sales efficiency, cash flow, or durability issues. A score below 40 can also reflect a deliberate investment posture.
McKinsey's analysis of more than 200 software companies from 2011 through 2021 found that businesses exceeded Rule of 40 performance only 16% of the time. BCG's 2025 private company analysis found 26% of companies above $80 million in revenue exceeded the rule, compared with 9% below $30 million. These are source specific observations, not an individualized benchmark.
Bessemer's Rule of X gives growth more weight in a late stage cloud valuation framework. SaaS Capital makes a related point: identical Rule of 40 scores can reflect different growth and profitability profiles. The standard calculation remains useful as a screen when its components are visible.
Three illustrative score profiles
| Profile | Growth | Margin | Score | What it shows |
|---|---|---|---|---|
| Growth first | 55% | Negative 15% EBITDA margin | 40 | A company can reach 40 while operating at a loss. The question is whether the growth is durable and what the investment is buying. |
| Balanced | 24% | 18% EBITDA margin | 42 | A modest surplus does not remove the need to inspect retention, new bookings, and operating discipline. |
| Margin first | 8% | 26% free cash flow margin | 34 | A higher margin does not replace the need to understand slower growth or the selected margin basis. |
These are hypothetical examples, not benchmarks or company comparisons.
What to examine after you calculate
- Retention and expansion: Is growth supported by durable gross and net revenue retention, or mostly by new bookings that have not yet proved durable?
- New customer economics: Is growth being purchased at a CAC payback and go to market spend level that still fits the company stage?
- Margin definition: What sits inside the selected profitability measure, including material adjustments or accounting choices?
- Investment posture: Does current product, infrastructure, sales, or market investment have an expected return and a date for review?
Calculation method and sources
This calculator does not normalize, adjust, annualize, or benchmark the values you enter beyond the formulas displayed. It keeps the selected growth basis, profitability basis, and period label attached to the result.
- Brad Feld: The Rule of 40% For a Healthy SaaS Company
A 2015 explanation of the formula, scaling context, recurring revenue basis, and profit-basis precision.
- Wall Street Prep: The Rule of 40
Formula, ARR and MRR context, EBITDA framing, and maturity considerations.
- Corporate Finance Institute: The SaaS Rule of 40 Explained
Formula context and discussion of growth and profitability basis variants.
- The SaaS CFO: The Rule of 40 SaaS
Recurring revenue mix and comparable-period guidance.
- BCG: Rule of 40 Lessons from the Top Performers in Software
2025 private-company analysis with scale context and operating drivers.
- McKinsey: SaaS and the Rule of 40
Historical software-company analysis covering Rule of 40 frequency, ARR growth, retention, payback, and free cash flow.
- Bessemer Venture Partners: The Rule of X
A late stage cloud valuation perspective that challenges equal weighting of growth and free cash flow margin.
- SaaS Capital: The Rule of 40 is Dead… Long Live the Rule!
A critique of treating different growth and profitability mixes as interchangeable.
- CloudZero: The rule of 40 in 2026
A vendor-authored perspective on AI infrastructure cost pressure and profitability margins.
Rule of 40 FAQs
How do you calculate the Rule of 40?
Add the growth rate to the selected profitability margin. This calculator derives growth from the current and comparable prior values, then calculates the selected margin against the revenue denominator you provide.
What is a good Rule of 40 score?
Forty is the common threshold. A score at or above 40 means the two components add to at least 40. The number needs context from the company stage, selected measurement bases, period, and durability of the underlying growth and margin.
Who popularized the Rule of 40?
Brad Feld popularized the metric in a 2015 post after describing a late stage investor's rule for SaaS companies. He also stressed the importance of being precise about the revenue and profitability measures used.
Is the Rule of 40 the same as a valuation?
No. It is a quick operating heuristic, not a valuation, diligence report, or price.
Should I use ARR growth or total revenue growth?
Either can be useful if the same basis is used for both periods and named in the result. ARR or annualized MRR is common for recurring revenue businesses, while total revenue is another possible basis.
Should I use EBITDA margin, operating income, or free cash flow margin?
EBITDA is a common choice. Operating income and free cash flow are also used in some contexts. They produce different results, so use a basis that fits the reporting question and keep it consistent when comparing periods.
Is the Rule of 40 useful for an early stage SaaS company?
It can be a reference point, but it becomes more useful as a company scales and its measurement periods become more comparable. A lower score can reflect an intentional investment posture, so it should not be read as a verdict.
What does a negative Rule of 40 score mean?
It means the growth rate and selected margin add to less than zero. Read it as a prompt to inspect both inputs and the selected period rather than as a complete conclusion about the business.
Can a company pass the Rule of 40 while losing money?
Yes. A company growing 55% with a negative 15% EBITDA margin scores 40. The total shows the mathematical tradeoff. It does not establish whether the growth is durable or the level of investment is appropriate.