ROAS Calculator
Every platform reports its own ROAS and every platform claims the same orders. This works out the return per channel, across paid together, and blended against the revenue the business actually took — which is the only one of the three that cannot be double-counted.
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If the channels together claim more revenue than the store took, at least one of them is being paid for somebody else’s work.
- The calculator
Channel ROAS, combined and blended
Two channels, your total store revenue and a target. Add a third channel by folding it into channel B.
Formula: channel ROAS = reported revenue ÷ that channel’s spend. Combined paid ROAS = all reported revenue ÷ all spend. Blended ROAS, sometimes called MER, = total store revenue ÷ total media spend. Paid share = reported revenue ÷ total store revenue. Spend allowed at target = reported revenue ÷ target. Nothing is sent anywhere — this runs entirely in your browser.
- Reading it
Which of these three to trust
Channel ROAS steers a campaign. Blended ROAS tells you whether the business got better.
Each platform decides for itself which orders it caused, using its own attribution window and its own modelling. Neither is dishonest, and both will happily claim the same order. That is why the fifth output matters: if the channels together claim more revenue than the store actually took, the combined figure is inflated by however much they overlap.
Blended ROAS — total store revenue over total media spend, sometimes called MER — cannot be double-counted, because the numerator comes from your own back office. It is a blunter instrument, and it includes revenue the advertising had nothing to do with, but it moves when the business moves. Use channel figures to steer and the blended figure to judge.
- ROAS on its own says nothing until you know the margin underneath it
- Platform revenue is gross — it counts orders that were later returned
- Watch blended ROAS over time rather than any single month in isolation
- Getting it wrong
Four ways ROAS misleads
Each of these makes a campaign look better than the bank statement does.
Summing platform revenue
Two platforms claiming the same order produce a total larger than the business took. The paid share output flags it the moment it goes over 100%.
Counting gross revenue
Platforms report the order at checkout, not after the return. On a category with meaningful returns this reorders which campaigns look best.
Judging ROAS without margin
A 4x return is excellent on a 40% contribution margin and loss-making on an 18% one. The number means nothing on its own.
Comparing prospecting to retargeting
Retargeting re-converts people other campaigns already reached, so it always wins on ROAS. Holding prospecting to that target is how growing accounts stop growing.
Our PPC guide covers the measurement model these four come out of, including running an incrementality test without a data team.
- Questions
ROAS FAQs
The questions this calculator usually raises.
What is the ROAS formula?
Revenue attributed to advertising divided by the cost of that advertising, expressed as a multiple. A 4x ROAS means four dollars of reported revenue for every dollar of media. Our ROAS definition covers the variations and where each is used.
What is the difference between ROAS and blended ROAS?
ROAS uses revenue the platform attributes to itself. Blended ROAS, often called MER, uses your total store revenue over your total media spend. The first can be double-counted across platforms; the second cannot, because the revenue figure comes from your own system.
What is a good ROAS?
Whatever sits comfortably above your break-even, which depends entirely on your margin. This calculator deliberately does not print a benchmark. Work out the floor first with the break-even ROAS calculator, then set a target above it.
Why is the paid share over 100%?
Because the platforms are claiming more revenue between them than the store took. It is normal for the figure to be high when several channels run together, and anything over 100% is proof that at least some orders are being counted twice.
Should I use ROAS or ROI?
Both, for different jobs. ROAS steers a campaign day to day; ROI tells you whether the investment paid. The ROI calculator works out the second from the same revenue and spend figures plus your margin.
Does this work for Amazon or other marketplaces?
The arithmetic does, but marketplace fees change the margin underneath it, so the target has to be set differently. Use the break-even ACoS calculator for the Amazon version, where cost is expressed as a share of sales rather than the other way round.
- Next
Related tools and reading
CALCULATOR
Sets the floor: the ROAS a campaign has to beat before it contributes anything at all.
CALCULATOR
The same revenue and spend, judged on what you keep rather than what you turned over.
Channels claiming more than the store took?
It is the most common reporting problem in paid media and it survives for years. The free audit reconciles platform-reported revenue against what the business actually banked.