What is ROAS?

ROAS (return on ad spend) is the sales your ads generate for each dollar spent on them. Amazon Ads gives the standard calculation as "(total ad sales) / (total ad spend)" in its ad products guide (checked 2026-10-03). A ROAS of 4.0 means $4 of attributed sales for every $1 of ad spend.

ROAS is ACoS turned upside down, and Amazon's ACOS guide calls it "the inverse of Amazon ACOS" (checked 2026-10-03). ACoS puts spend on top and reads as a cost. ROAS puts sales on top and reads as a return. Neither tells you anything about profit until you compare it with your margin.

The formula

ROAS = Attributed Sales ÷ Ad Spend
ROAS = 100 ÷ ACoS (%)

ROAS is written in three ways that mean the same thing: a multiple (4.0), a ratio (4:1) or a percentage (400%). Check which one a report uses before comparing two of them, because a ROAS of 4 and a ROAS of 4% are very different results.

Worked example

The figures below are example inputs chosen for round arithmetic. They are not taken from any account.

Suppose a campaign spends $1,000 in a month and Amazon attributes $4,000 of sales to it.

• ROAS = $4,000 ÷ $1,000 = 4.0
• ACoS = $1,000 ÷ $4,000 × 100 = 25%
• Check: 100 ÷ 25 = 4.0

Now add the product's economics, again as example inputs: each order sells for $30, Amazon's fees take $8 and the landed cost is $7, which leaves $15 of contribution margin before advertising. At a ROAS of 4.0, each $30 order carries $7.50 of ad cost, so it keeps $7.50 of its margin.

Find your break-even ROAS

The ROAS at which advertising takes the whole margin is the inverse of break-even ACoS:

Break-Even ROAS = Price ÷ Contribution Margin

For the example product, break-even ROAS = $30 ÷ $15 = 2.0. Below 2.0, every advertised order costs more in ads than it contributes. Above it, the difference is profit.

The same arithmetic shows why no single ROAS can be called good. Take a second example product that also sells for $30 but leaves only $6 of margin. Its break-even ROAS is $30 ÷ $6 = 5.0, so the 4.0 that is comfortable for the first product loses money on every advertised order of the second. Work out your own with the break-even ACoS calculator, then invert the result: break-even ROAS = 100 ÷ break-even ACoS.

How to use ROAS to make decisions

Set a floor, then a target. Break-even ROAS is the floor. The target sits above it by however much margin you want to keep. Keeping half of the example's $15 margin means spending $7.50 per $30 order: a target ACoS of 25%, which is a target ROAS of 4.0.

Judge changes by what the extra spend returned. A campaign's ROAS is an average across every keyword and every click. When you raise a bid or a budget, the question is what the additional spend brought back, and that can sit well above or below the average. Example inputs: a budget rise takes spend from $1,000 to $1,500 and attributed sales from $4,000 to $5,000. Average ROAS only falls to 3.33, but the extra $500 bought $1,000 of sales, a ROAS of 2.0 on the increment. Against a 2.0 break-even, that extra spend made nothing. Compare windows of the same length that have had time to settle.

Push decisions down to where bids live. A healthy account ROAS can hide keywords and targets well below break-even. Find them at that level and adjust their bids. The bid optimization guide walks through turning a target into a bid.

Common mistakes

• Reading revenue as profit. ROAS counts sales, not margin. A ROAS of 3.0 sounds healthy and still loses money on any product whose break-even ROAS is above 3.0.
• Averaging ratios across campaigns. Example inputs: campaign A spends $100 for $800 of sales (8.0) and campaign B spends $900 for $1,800 (2.0). The average of the two ratios is 5.0, but together they returned $2,600 on $1,000, a ROAS of 2.6. Add up sales and spend, then divide.
• Mixing formats. 4.0, 4:1 and 400% are the same result. Converting one to another by eye is where reports go wrong.
• Judging fresh data. Amazon reports ad sales on the date of the click and says attribution metrics for a date "remain incomplete until the lookback window has ended" (Amazon Ads attribution help, checked 2026-10-03), so the latest days understate ROAS. See attribution window.
• Confusing ROAS with ROI. Amazon's ad products guide describes ROI as "how much net profit you earn for every dollar you spend". ROAS stops at revenue and ignores fees and cost of goods.
• Comparing ad types on one number. The same Amazon guide describes Sponsored Products ACOS as measured against promoted product sales and Sponsored Brands ACOS against overall brand sales, so a ROAS from each is not measuring quite the same thing.

How ROAS relates to other metrics

ROAS describes the ads. To see what advertising costs the whole business, organic sales included, read TACoS.

How Shurq helps

• ROAS, ACoS and TACoS in one place. ROAS is available as a dashboard card tile next to ACoS and TACoS, so the ratio and its inverse are never more than a glance apart.
• Targets in ACoS, from your own break-even. Shurq sets targets as an ACoS. To work from a ROAS goal, convert it: target ACoS = 100 ÷ target ROAS, so a ROAS goal of 4.0 is a 25% target. Ad Manager measures break-even from your own profit and loss, only for products with a cost of goods on file, so the floor comes from your numbers rather than a rule of thumb.
• Bids priced toward the target. The Bid Optimizer prices every bid toward your target and can cap raises at the bid where a click still pays back at that target.