Return on ad spend measures attributed revenue for each advertising dollar. Whether that return is enough depends on your product economics. This free ROAS calculator connects campaign results with your contribution margin, so you can set a target for Amazon, Google, Meta, or other advertising.
How to use this calculator
Use spend and attributed sales from the same period and attribution basis. Enter your margin after product, shipping, and selling costs but before ads. Add a desired margin after advertising. Average order value and click-to-order conversion rate are only needed for the optional CPC model.
Formula and assumptions
ROAS = attributed sales ÷ ad spend. ACoS = ad spend ÷ attributed sales × 100. Break-even ROAS = 1 ÷ pre-ad contribution margin as a decimal. Target ROAS = 1 ÷ (pre-ad margin − target margin). Maximum CPC = average order value × conversion rate × margin available for ads.
Worked example
$4,000 attributed sales on $1,000 spend produces 4× ROAS and 25% ACoS. At a 40% pre-ad contribution margin, $600 remains after ads. Break-even ROAS is 2.5×. Keeping a 10% contribution margin after ads requires about 3.33× ROAS.
Common questions
What is a good ROAS?
A useful target starts with your costs and profit requirement. The same ROAS can produce positive contribution for one product and a loss for another. This calculator uses your inputs instead of a universal benchmark.
Can I use total store revenue?
Total revenue divided by total ad spend is a blended efficiency measure. Keep that separate from attributed ROAS, and do not mix those revenue bases when comparing campaigns.
