What is Rule of 40? (Definition + SaaS example)
The Rule of 40 is a SaaS performance benchmark stating that a healthy software company's combined revenue growth rate and profit margin should equal or exceed 40%. It balances growth and profitability — a company growing at 60% with a -20% margin passes, as does a company growing at 10% with a 30% margin.
Formula and Calculation
Rule of 40
Rule of 40 Score = Revenue Growth Rate (%) + EBITDA Margin (%)
Revenue growth is typically measured as year-over-year ARR growth. Profit margin is typically EBITDA margin or free cash flow margin.
Worked SaaS Example
Three SaaS companies at $20M ARR demonstrate different paths to the Rule of 40:
| Company | ARR Growth | EBITDA Margin | Rule of 40 Score | Verdict |
|---|---|---|---|---|
| HyperGrowth Inc. | 70% | -25% | 45 | Passes — growth justifies losses |
| BalancedCo | 30% | 15% | 45 | Passes — balanced approach |
| CashCow SaaS | 8% | 35% | 43 | Passes — profitability offsets slow growth |
| StrugglingCo | 20% | -5% | 15 | Fails — neither growing fast nor profitable |
Rule of 40 Over Company Lifecycle
| Stage | Typical Growth | Typical Margin | Score Range |
|---|---|---|---|
| Seed to Series A ($1–5M ARR) | 80–200% | -50% to -100% | Not meaningful |
| Growth ($5–30M ARR) | 40–100% | -30% to 0% | 20–60 |
| Scale ($30–100M ARR) | 25–50% | 0% to 20% | 30–55 |
| Mature ($100M+ ARR) | 10–30% | 15–35% | 35–55 |
Why Rule of 40 Matters for SaaS
Finance teams use the Rule of 40 as a governance framework for resource allocation. When the score is well above 40, there is room to invest more aggressively in growth. When it is below 40, the team must decide whether to cut costs or find more efficient growth channels. It prevents the common trap of growing at all costs without regard for unit economics.
In investor reporting, the Rule of 40 is a standard benchmark in board decks, earnings calls, and fundraising materials. Investors use it as a quick filter — companies consistently above 40 command premium valuation multiples. The score is especially important during market downturns when profitability matters more than growth.
A common mistake is optimizing for the Rule of 40 score by cutting growth investment to boost margin. This can produce a passing score in the short term while damaging long-term competitiveness. The Rule of 40 works best as a balanced scorecard — both components should be trending in the right direction.
The Rule of 40 connects to ARR growth as the primary revenue input, and to burn rate which directly impacts the margin component. Companies with high NRR often score well because strong net retention drives capital-efficient growth.
Track your Rule of 40 score in JustPaid
Frequently Asked Questions
Rule of 40 Score = Revenue Growth Rate (%) + Profit Margin (%). Revenue growth is typically year-over-year ARR growth. Profit margin is typically EBITDA margin, though some companies use free cash flow margin. A score of 40 or higher indicates a healthy balance of growth and profitability.
Related Terms
ARR (Annual Recurring Revenue)
Annual Recurring Revenue (ARR) is the annualized value of a SaaS company's committed recurring subscription revenue. ARR equals MRR multiplied by 12 and usually excludes one-time fees, services, and purely variable usage, making it a standard metric for investor reporting, valuation, and annual planning.
Burn Rate
Burn rate is the speed at which a company spends its cash reserves, typically measured as net cash outflow per month. In SaaS, burn rate determines runway — the number of months a company can continue operating before running out of cash, making it the most watched metric at pre-profit startups.
NRR (Net Revenue Retention)
Net Revenue Retention (NRR) measures the percentage of recurring revenue retained from existing customers over a period, including expansion, contraction, and churn. An NRR above 100% means a SaaS company is growing revenue from its existing customer base without acquiring a single new customer.
