ROAS Calculator

Measure your return on advertising spend and break-even ROAS.

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About this calculator

ROAS — return on advertising spend — is the revenue you get back for every pound you put into ads. A ROAS of 4 means £4 of revenue per £1 of spend. On its own, though, ROAS can flatter a losing campaign: revenue is not profit. That is why this calculator also computes your break-even ROAS from your gross margin — the minimum ROAS at which a campaign stops losing money. If your margin is 25%, you need a ROAS of at least 4 just to break even.

The formula

ROAS = Ad revenue ÷ Ad spend Break-even ROAS = 1 ÷ (Gross margin ÷ 100)

Worked example

You spend £1,000 on ads and attribute £4,000 of revenue to them. Your gross margin is 30%.

ROAS = £4,000 ÷ £1,000 = 4.0x
Break-even ROAS = 1 ÷ 0.30 = 3.33x

You are above break-even — the campaign is profitable on gross margin.

Common mistakes

Judging campaigns on ROAS alone without knowing the break-even ROAS for your margin.
Using revenue including VAT, which inflates ROAS by 20%.
Ignoring attribution limits — platform-reported revenue often overstates what the ads truly caused.

Frequently asked questions

Whatever is comfortably above your break-even ROAS. E-commerce businesses often target 3–5x, but a 10x ROAS on a 5% margin product still loses money.

ROAS compares revenue to ad spend. ROI compares profit to total cost. ROAS of 4x with a 30% margin is an ROI of about 20%.

For a true picture, yes — add management fees and creative costs to the spend figure. Platforms report media-only ROAS.

Assumptions & limitations

Assumes the revenue you enter is genuinely attributable to the ad spend, and that gross margin is constant across advertised products.

Sources & verification

This calculator applies the standard formula published above to the figures you enter — it relies on no external statutory data. The formula and the worked example were checked by hand against each other.

Formula last verified: 24 July 2026

Maintained by: Steve Davis, Founder & Editor — see our editorial standards

Spotted an error or an out-of-date figure? Report it — corrections are prioritised over all other work (see our corrections policy).