What the Rule of 40 actually measures
It is a single-number proxy for whether a SaaS company is balancing growth and efficiency. A company growing 60% with -20% margin and a company growing 20% with +20% margin both score 40 — the rule is agnostic about which side carries the weight.
The growth input is YoY recurring revenue, not total revenue (services, one-time, and pass-through fees distort it). The margin input is usually EBITDA margin, though many late-stage operators use FCF margin because it captures working-capital effects EBITDA misses.
How investors read the output
- Below 20: structural problem. The story has to be a near-term inflection (M&A, pricing, segment exit), not "we'll grow into it."
- 20 – 40: below the bar but defensible if the trajectory is improving. Show the path back.
- 40 – 60: healthy. This is where most public SaaS companies sit at scale.
- Above 60: exceptional. Either real (rare) or one of the inputs is being measured generously.
Common ways the score is gamed
Excluding one-time costs. Adding back equity comp or restructuring inflates margin. Investors back it out before scoring.
Annualising the wrong window. Growth is YoY, not quarter-over-quarter annualised. A QoQ jump from a price increase can flatter the growth side for a quarter.
Counting services revenue. Implementation revenue grows faster than ARR early on. Strip it and rerun.
What to do when you are below 40
Below the bar, the move depends on which side is dragging. If growth is slow but margin is fine, the lever is GTM efficiency — channel mix, expansion motion, pricing. If margin is the drag, the lever is COGS (gross margin) and headcount efficiency (revenue per employee, payback). Fairview's margin-leak diagnostic typically surfaces 200–600 basis points of EBITDA hiding in COGS allocation, pricing leakage, and headcount-to-output ratios.