What is ROAS and how to calculate it

What this guide helps you decide

Primary: understand revenue return and its limits before making spending decisions.

• Choose one attribution window
• Divide attributed revenue by spend
• Keep revenue return separate from contribution profit

The definition

ROAS stands for return on ad spend. It answers a narrow question: for each pound spent on advertising, how many pounds of revenue did the ads get credit for? The formula is simple.

ROAS = revenue attributed to ads divided by advertising spend

You will see it written as a ratio, such as 3.5 or 3.5 to 1, or as a multiple, 3.5x. Some platforms show it as a percentage, where 350 per cent means the same thing. All forms describe one calculation, and the first job when reading any dashboard is to confirm which form it uses.

A worked example

Suppose a store runs a campaign for a week. It spends 500 pounds and the platform reports 35 purchases, each at an average order value of 50 pounds. Attributed revenue is 35 times 50, which is 1,750 pounds. ROAS is 1,750 divided by 500, which is 3.5.

This does not yet say whether the campaign made money. It says only that the ads were credited with 3.50 pounds in revenue per pound spent. To judge profit you need the costs behind that revenue, which we cover below. Use the calculator on this page to try your own numbers.

What ROAS leaves out

ROAS is popular because it is easy, but its simplicity hides several things.

• Cost of goods. A pound of revenue on a product with a 30 per cent margin is worth far less than a pound on a product with a 70 per cent margin.
• Shipping, packaging and payment fees. These reduce contribution on every order.
• Returns. Revenue that is refunded was never really revenue.
• Repeat purchases. A first order can be worth more than its basket value if customers return, which is the territory of lifetime value.
• Other costs of acquiring the sale. Creative production, agency fees and tools are not in the formula.

Because of these omissions, two stores with the same ROAS can have very different results. One is comfortably profitable and the other loses money on every order.

From ROAS to profit

The bridge is break-even ROAS, which is the ROAS at which an order covers its direct costs and the ad spend. It equals the order value divided by contribution per order before advertising. If your 50 pound order leaves 20 pounds of contribution, break-even ROAS is 2.5. A campaign returning 3.5 is above that line. A campaign returning 2.0 is below it and, on first orders alone, loses money.

The break-even ROAS guide explains the calculation in detail, and the break-even ROAS calculator works it out. The profit after ad spend calculator shows the result in pounds.

Using the hypothetical campaign

Continue the earlier example. Each 50 pound order leaves 20 pounds of contribution, so 35 orders produce 700 pounds. Subtract the 500 pounds of ad spend, leaving 200 pounds. The campaign made a modest profit on first orders in this invented case. If returns had been 10 per cent and you had not accounted for them, the true figure would be lower. Adding even one extra cost, such as 2 pounds of packaging per order, would take off another 70 pounds. This is why a ROAS figure alone is a prompt to dig, not an answer.

What attribution means for ROAS

The revenue in the numerator is attributed by a platform, a store analytics tool or a third-party tool, and each uses rules that can differ. Common differences include the attribution window, such as how many days after a click or a view a purchase can be credited, whether view-through conversions count, and how multiple touchpoints are shared. A platform may report a higher ROAS than your store records because it counts purchases that other channels also claim.

None of these is necessarily wrong, but they are not interchangeable. When you compare ROAS across channels or time periods, use the same source and the same settings. For a store-wide view that avoids attribution disputes, see MER versus ROAS.

ROAS and related metrics

ROAS sits among a family of ratios, and each answers a different question.

CPA and ROAS are two views of the same data. With an average order value of 50 pounds and a ROAS of 3.5, the cost per purchase is about 14.29 pounds. The CPA calculator and the CPA versus CAC guide explain how these connect.

How to use ROAS well

Set a target from your margins

Work out break-even ROAS first, then add a buffer for the profit you want. If break-even is 2.5 and you want a margin of safety, a working target might be 3. The target belongs to your store and your products, not to an industry average. See what is a good ROAS for a method.

Compare like with like

Compare campaigns in the same period, with the same attribution settings, and similar products. A prospecting campaign aimed at new customers usually looks different from a campaign aimed at past visitors, because past visitors are closer to buying and often show a higher ROAS that is partly credit for sales that were already likely.

Look at volume as well

A tiny campaign with ROAS 8 may be impressive but small. If scaling it lowers ROAS, the total profit can be higher at ROAS 4 with much more revenue. Look at absolute profit as well as ratios.

Read the trend

One day of ROAS is noise. Look at a sensible window, and be wary of reacting to a bad day. The interpret ad ROAS guide offers more on reading changes.

Common mistakes

• Treating ROAS as profit. It is a revenue ratio.
• Ignoring returns. Use net revenue where you can.
• Comparing across attribution settings. A seven day click figure and a one day click figure are different measurements.
• Using an industry benchmark as your target. Benchmarks ignore your margins.
• Cutting prospecting because its ROAS is lower. Sometimes the campaign that looks worse is feeding the campaign that looks better.

Scope and attribution cautions

This guide is general education. The figures are hypothetical. Your own margins, return rates and attribution determine what a given ROAS means for you. Platform numbers are the platform's own estimates, and small samples can mislead, so avoid making large decisions on a handful of orders.

Reading a ROAS figure step by step

When you see a ROAS number in a dashboard, run a short checklist before reacting. First, which spend is in the denominator: one campaign, one account, or all channels? Second, which revenue is in the numerator: purchase value including tax and shipping, or net of them? Third, what attribution window applies, and does it include view-through conversions? Fourth, how many orders sit behind the figure? A ROAS of 6 from three orders is much weaker evidence than a ROAS of 3 from three hundred. Fifth, what was the period, and did a promotion or holiday fall inside it?

Suppose a campaign shows ROAS 4.2 on 5 orders and another shows 2.9 on 120 orders. The first looks better but is far less reliable. A sensible response is to keep watching the first rather than shift all spend to it, and to treat the second as a more trustworthy estimate of what scaling may produce. This kind of reading takes a minute and prevents most reactive mistakes.

ROAS for different business models

The same formula behaves differently depending on how you sell. A store with a single product and high repeat purchase may accept a modest first-order ROAS. A store selling a one-off, high-consideration item, such as furniture, has little repeat revenue and needs first-order profit. A store with wide margins differences between products needs product-level ROAS instead of one blended figure. Subscription businesses should look at the first payment and the expected number of payments, while stores that depend on gifting see strong seasonal swings. Whichever applies to you, write down the assumptions behind your target so that you can revisit them when the business changes.

Revenue ROAS definition card

Illustrative worked example, not a measured customer result. Replace assumptions with checked facts.

Common questions

What is the ROAS formula?

Revenue attributed to ads divided by ad spend. Spending 200 pounds and being credited with 800 pounds gives a ROAS of 4.

Is ROAS the same as ROI?

No. ROAS compares revenue with ad spend. Return on investment usually compares profit with total cost, so it accounts for margins and other expenses.

Can ROAS be below 1 and still be fine?

Sometimes, if lifetime value from repeat purchases justifies it, but that is an assumption you should test and state. On first orders alone, a ROAS below 1 means you receive less revenue than you spent on the ads.

Why does my platform ROAS differ from my store numbers?

Different attribution rules and windows. Choose a primary source and use it consistently.

How often should I check ROAS?

Check regularly, but make decisions on a window long enough to include enough orders. Daily swings are often noise.

Does a high ROAS mean I should spend more?

Not automatically. Returns often fall as spend rises, so scale in steps and watch profit.