ACoS and ROAS Calculator.
Enter your ad spend and the sales those ads produced to see ACoS and ROAS side by side. Or convert one into the other if you only have a single number.
How it is calculated.
ACoS and ROAS describe the same relationship from opposite directions. ACoS asks what share of your ad sales went back out as ad cost. ROAS asks how many dollars of ad sales each ad dollar produced.
ROAS = ad sales ÷ ad spend
ROAS = 1 ÷ ACoS, and ACoS = 1 ÷ ROAS
ACoS is written as a percentage and lower is better. ROAS is written as a multiple and higher is better. Because one is the inverse of the other, a small move at a low ACoS is a big move in ROAS, which is why the two can feel like they disagree when they do not.
A worked example.
This is an illustrative example with made-up numbers for a fictional brand. Northlane Goods spent $1,250 on Sponsored Products last week, and those ads produced $5,000 in sales.
| Ad spend | $1,250.00 |
| Ad sales | $5,000.00 |
| ACoS: 1,250 ÷ 5,000 | 25.0% |
| ROAS: 5,000 ÷ 1,250 | 4.00x |
Every $1 of ad spend produced $4 of ad sales. Going the other way, a 25% ACoS converts to 1 ÷ 0.25, which is the same 4.00 ROAS.
What to do with the number.
Compare it with your break-even, not with someone else's average. A 25% ACoS is healthy for one product and a loss for another. The break-even ACoS calculator gives you the ceiling for your own costs, and what is a good ACoS on Amazon covers how to set a target under it.
Pick one and use it consistently. Amazon's console leads with ACoS, while most other ad platforms and many agencies report ROAS. The Amazon ROAS guide explains when each is the clearer way to talk about the same result.
Look past ad sales. Neither number sees organic sales. ACoS vs TACoS explains the wider view, and the TACoS calculator works it out from your totals.
Read it alongside the other core metrics. ACoS moves when click cost or conversion rate moves. The Amazon PPC metrics that matter shows how to tell which one changed.
Frequently asked questions.
What is ACoS?
ACoS stands for advertising cost of sale. It is ad spend divided by the sales those ads produced, written as a percentage. If you spend $25 on ads and they produce $100 in sales, your ACoS is 25%.
What is ROAS?
ROAS stands for return on ad spend. It is ad sales divided by ad spend, written as a multiple. If $25 of ad spend produces $100 in sales, your ROAS is 4, sometimes written 4x or 4.0.
How do I convert ACoS to ROAS?
Divide 1 by the ACoS written as a decimal. A 20% ACoS is 1 divided by 0.20, which is a ROAS of 5. A 50% ACoS is a ROAS of 2.
How do I convert ROAS to ACoS?
Divide 1 by the ROAS and write the result as a percentage. A ROAS of 4 is 1 divided by 4, which is 0.25, or a 25% ACoS. A ROAS of 2.5 is a 40% ACoS.
Is a lower ACoS always better?
Not always. A very low ACoS can mean you are only bidding on your safest terms and leaving sales on the table. What matters is whether your ACoS sits under your break-even point and matches what you want the campaign to do, whether that is profit, launch or defending a ranking.
Does ACoS include organic sales?
No. ACoS and ROAS only count sales attributed to ads. To measure ad spend against all sales, including organic, use TACoS, which is ad spend divided by total sales.