Zway.ai
Book a demo

Free tool

Your Rule of 40 score, and what it costs to move it

Rule of 40 adds your growth rate to your profit margin and asks whether the total clears forty. This calculates the score, shows the gap, and prices both ways of closing it against your ARR. It is an investor convention rather than a law, and it means little before real scale.

Last reviewed 27 August 2026

%
%

Negative is normal for a company still buying growth.

$
$

Your blended cost of acquisition per dollar of annual recurring revenue.

Result

Rule of 40 score

35.0

60% growth plus -25% EBITDA margin

Short of the benchmark by

5.0 points

Benchmark set to 40

Three ways to reach the benchmark

Three ways to reach the benchmark
RouteGrowthMarginWhat it takes
Grow faster only65%-25%$100,000 of extra new ARR, costing about $120,000
Improve margin only60%-20%$100,000 of annual cost removed
Split it evenly63%-23%$60,000 spent plus $50,000 cut

Cutting cost is cheaper in cash terms here, at $100,000 against $120,000. It is also faster, and it is the only one of the two you fully control. Treat the score as a summary, not a target. A company at ten million ARR is being measured by it. A company at three hundred thousand is not, and optimising for it at that size usually means underinvesting in growth.

How this works

What the numbers mean.

  • 01The score is simply growth rate plus profit margin, both as percentages. Nothing is weighted, which is the point: it says a dollar of growth and a dollar of profitability are interchangeable at the margin.
  • 02Closing the gap by growth is priced using your cost to add a dollar of new ARR, so one point of score costs one percent of ARR multiplied by that figure. Closing it by margin is priced as annual cost removed, one for one.
  • 03Both routes are shown at full size and split evenly, because in practice most companies move both slightly rather than one dramatically.

Assumptions and limits

  • Rule of 40 is a convention that spread through SaaS investing. It is not a researched threshold, and no standard exists for which margin to use, which is why the basis is an input here.
  • The benchmark is close to meaningless below a few million in ARR. A seed company growing 300 percent while burning heavily scores well for reasons that say nothing about the business.
  • The cost of a point of growth assumes your acquisition cost holds as you spend more. It rarely does, so treat the growth route as the optimistic side.

Questions about this tool

Which margin should I use?
EBITDA margin is the most common in public SaaS reporting, free cash flow margin is the most honest for a private company because it includes working capital, and net income margin is the strictest. Pick one and stay with it. Switching basis between quarters is how a flat score turns into an improving one on paper.
Is 40 a real threshold?
It is a convention, not a finding. It became shorthand among SaaS investors for a company balancing growth and efficiency, and it stuck because it fits on a slide. Treat it as a conversation starter with an investor rather than a number that determines whether your business works.
Does this apply to a seed-stage company?
Not usefully. Early companies grow at rates that make the score meaningless, and the margin side is dominated by fixed costs that have nothing to do with efficiency. The score starts carrying information somewhere around the point where growth rate drops below one hundred percent a year.
Why does the growth route cost more than the margin route?
Because acquiring revenue costs more than a dollar per dollar for most companies, while cutting a dollar of cost saves exactly a dollar. The trade is that growth leaves you with an asset that recurs and cost cutting leaves you smaller. Cash cost alone is the wrong way to choose between them.

Related

This tool is free and there is nothing to sign up for. If you would rather have the work done than calculate it, that is what Zway does.

All toolsBook a demo