Free B2B marketing tool

CAC Payback & SaaS Efficiency Calculator

Calculate CAC payback, SaaS magic number, burn multiple and Rule of 40 using explicit period and margin assumptions. Download your SaaS efficiency results.

No sign-up. Clear method. Downloadable results.

Start with your inputs.

Enter your own figures, review the calculation and export the results. Defaults are illustrative examples.

Allowed: 0 to 1,000,000,000,000.
Allowed: 0.01 to 1,000,000,000,000.
Enter a percentage between 0 and 100. Allowed: 0.01 to 100.
Allowed: 0 to 1,000,000,000,000.
Allowed: 0 to 1,000,000,000,000.
Allowed: 0.01 to 1,000,000,000,000.
Allowed: -1,000,000,000,000 to 1,000,000,000,000.
Allowed: 0 to 1,000,000,000,000.
Allowed: -100 to 1,000.
Allowed: -1,000 to 100.

Illustrative example

Your results.

Applies to monetary outputs only. No amount conversion.

Complete valid inputs to see results.

Estimates depend on your assumptions. No inputs are sent or saved by this tool.

Method and definitions

CAC payback = CAC ÷ (monthly revenue per customer × gross margin). Magic number = (current-quarter recurring revenue − prior-quarter recurring revenue) × 4 ÷ prior-quarter sales + marketing spend. Burn multiple = net cash burn ÷ net new ARR. Rule of 40 = annual revenue growth % + operating profit margin %.

Use recognised recurring revenue for the magic number, not ARR. Burn and net new ARR must refer to the same period; burn multiple is not meaningful for zero or negative net new ARR. Payback ignores churn and expansion. Rule of 40 uses the operating margin you supply, not EBITDA or cash margin. These are distinct planning metrics.

Reference: Scale Venture Partners: Magic Number Math.

Reference: David Sacks: The Burn Multiple.

Worked example

$3,000 CAC at $500 monthly revenue and 80% margin gives 7.5-month payback. $50,000 quarterly revenue growth and $100,000 prior-quarter acquisition spend give a magic number of 2.

Use this tool in your workflow

  1. Replace the example inputs with your own figures or facts.
  2. Use matching definitions, units and reporting periods.
  3. Review the method and scope before applying the output.
  4. Copy or download the results for your next planning discussion.

For help turning a plan into a campaign, explore Qualent Media’s B2B campaign strategy services.

A clear basis for your next step

Questions, answered.

Understand the method and the boundaries of the result.

How does this cac payback & saas efficiency calculator work?

CAC payback = CAC ÷ (monthly revenue per customer × gross margin). Magic number = (current-quarter recurring revenue − prior-quarter recurring revenue) × 4 ÷ prior-quarter sales + marketing spend. Burn multiple = net cash burn ÷ net new ARR. Rule of 40 = annual revenue growth % + operating profit margin %.

How should I interpret the result?

Use recognised recurring revenue for the magic number, not ARR. Burn and net new ARR must refer to the same period; burn multiple is not meaningful for zero or negative net new ARR. Payback ignores churn and expansion. Rule of 40 uses the operating margin you supply, not EBITDA or cash margin. These are distinct planning metrics.

Can I download my results?

Yes. CSV export includes the inputs, unrounded numeric results where applicable, method and scope. Copy results is also available; if clipboard access is unavailable, a text download is provided. This tool runs in your browser without sending or storing your inputs.

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