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CPA and ROAS calculator

Cost per acquisition and return on ad spend from spend, conversions, and revenue. Runs in your browser; nothing you type is sent anywhere.

Formula

ROAS equals revenue attributed to advertising divided by advertising cost. $40,000 in attributed revenue on $10,000 of spend is a ROAS of 4, written 4x or 400 percent. Breakeven ROAS equals one divided by the contribution margin rate before marketing.

The revenue figure comes from an attribution model with a window, so the same campaign has several ROAS values depending on who is counting. State the source and window with every ROAS, and use MER (total revenue over total marketing spend) as the check.

Typical ranges are on the benchmarks pages; definitions in the glossary.

Reference

A reference library for digital advertising, written and reviewed by the Agency Echelon team. Free to read. No advertising, no sponsorship, no affiliate links, no email gate.

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Reviewed September 23, 2026. Reference text is licensed CC BY 4.0. Privacy