Rule of 40

What is the Rule of 40?

The Rule of 40 states that a healthy SaaS company's growth rate plus profit margin should equal or exceed 40%. It's a balancing test that allows for different strategies while ensuring overall efficiency.

A company growing 50% with -10% margins scores 40. A company growing 20% with 20% margins also scores 40. Both are considered healthy by this benchmark.

Why the Rule of 40 Matters

The Rule of 40 acknowledges that growth and profitability are trade-offs. Young companies sacrifice profits for growth. Mature companies sacrifice growth for profits. This metric lets you compare them fairly.

Investors use it as a quick health check. Companies consistently above 40 command premium valuations. Those below 40 face harder questions about their path to efficiency.

How to Calculate the Rule of 40 Step by Step

Step 1: Calculate your revenue growth rate. Use trailing 12-month ARR growth. Pull your ARR from 12 months ago and your current ARR.

• ARR 12 months ago: $1,200,000
• Current ARR: $1,920,000
• Revenue Growth Rate = ($1.92M - $1.2M) ÷ $1.2M = 60%

Step 2: Calculate your profit margin. You can use EBITDA margin, operating margin, or free cash flow margin. EBITDA margin is most common for this calculation.

• Trailing 12-month revenue: $1,800,000
• Trailing 12-month EBITDA: -$180,000
• EBITDA Margin = -$180K ÷ $1.8M = -10%

Step 3: Add them together.

• Rule of 40 Score = 60% + (-10%) = 50 ✓

You're above 40. Growth is more than compensating for your losses.

Step 4: Understand what the score means for your stage.

• Pre-Series A: Focus on growth rate. Negative margins are fine if growth is 80%+
• Series A-B: Should be trending toward 40. Acceptable to be below if growth is strong
• Series C+: Should consistently hit 40+. Investors expect efficiency at scale

Step 5: Track the components over time. The Rule of 40 is most valuable as a trend. Are you improving toward 40, or drifting away? If growth is slowing, margins should be improving to compensate.

Common mistakes founders make:

• Mixing up revenue growth rate with MRR growth rate (use ARR YoY growth)
• Using gross margin instead of EBITDA/operating margin
• Comparing against companies at different stages (a $2M ARR startup shouldn't benchmark against a $100M company)
• Ignoring that the Rule of 40 is a guideline, not a law. Context matters

Rule of 40 Benchmarks

Below 20: Struggling. Neither growing fast nor profitable. 20-40: Acceptable. Room for improvement. 40-60: Healthy. Well-balanced business. Above 60: Elite. Top-tier SaaS performance.