How to use it
Tap ROAS, Revenue or Ad spend in the equation to pick the unknown. ROAS can be typed as a plain number, with an x, or as a percentage: 4, 4x and 400% all mean the same here. The result always shows both the ratio and the percentage, because different tools report it differently: Google Ads expresses target ROAS as a percentage, while many dashboards show a multiple.
The formula
ROAS = revenue ÷ ad spend
Revenue = ROAS × ad spend
Ad spend = revenue ÷ ROAS
Google's Target ROAS help page gives the percentage form: $5 in sales ÷ $1 in ad spend × 100% = 500%. Same number as a ratio: 5x.
Worked examples
Finding ROAS. A month of shopping ads cost $3,000 and the platform attributes $12,600 of revenue to them. $12,600 ÷ $3,000 = 4.20x, or 420%.
Revenue a target needs. You plan $2,000 of spend and want a 3.5x ROAS. $2,000 × 3.5 = $7,000 of attributed revenue.
Spend a revenue goal allows. You expect $10,000 of revenue and must keep ROAS at 400% or better. $10,000 ÷ 4 = $2,500 maximum spend.
| Revenue | Ad spend | ROAS | ACoS |
|---|---|---|---|
| $12,600 | $3,000 | 4.20x (420%) | 23.81% |
| $7,000 | $2,000 | 3.50x (350%) | 28.57% |
| $10,000 | $2,500 | 4.00x (400%) | 25.00% |
ROAS and ACoS
Amazon Ads reports advertising cost of sales (ACoS): ad spend divided by attributed sales, as a percentage. It is ROAS turned upside down. A 4x ROAS is a 25% ACoS, and a 25% ACoS is a 4x ROAS. The calculator shows ACoS next to every result so you can move between Amazon reports and everything else.
ACoS = ad spend ÷ revenue × 100 = 1 ÷ ROAS × 100
What ROAS does not tell you
ROAS uses revenue, not profit. A 3x ROAS is excellent for a product with an 80% margin and a loss for one with a 20% margin, because the product costs come out of the revenue before anything is left to pay for the ads. To see the line between profit and loss, use the break-even ROAS calculator. To count product costs and judge the whole campaign, use the marketing ROI calculator.
The revenue figure also depends on attribution. Two platforms can claim the same sale, and a click-through window of 7 days gives a different number from 28 days. When comparing campaigns, keep the attribution setting the same.
How this calculator handles your numbers
The sums run on exact fractions. ROAS is shown to two decimals with an x, money to two decimals, and percentages to two decimals, all rounded half away from zero. If you type a bare ROAS above 20, the calculator reads it as a ratio and says so, in case you meant a percentage: type 250% for 2.5x. A zero spend or zero ROAS, where division breaks down, gets a message instead of a result.