How to Calculate ROAS: The Formula, Break-Even ROAS and What Your Number Really Means

ROAS, or return on ad spend, is the number every ad platform puts at the top of its dashboard, and the one small business owners most often misread. This guide is for owners and marketers running Google, Meta, Amazon or local ads who want to know how to calculate ROAS correctly, what ROAS they need to break even, how it differs from ROI, CAC and ACoS, and why the figure your ad account reports may not match your bank balance. Every example uses US dollars and real cost lines, so you can plug in your own numbers.

Quick answer

ROAS = revenue from ads ÷ ad spend. $6,000 of sales from $1,500 of ads is a ROAS of 4 (also written 4:1, 4x or 400%). To know whether that's profitable, compare it with your break-even ROAS = 1 ÷ contribution margin. With a 40% margin, you break even at 2.5 and anything above it adds profit.

• Count revenue before sales tax and after discounts, refunds and returns

• Count all ad costs in spend, including agency, creative and tool fees if you want the true picture

• Contribution margin = price minus product cost, shipping, card fees, returns and other per-order costs

• Target ROAS for a profit goal = 1 ÷ (margin − target profit %)

• Platform ROAS usually runs higher than reality; check blended ROAS (total revenue ÷ total ad spend)

The ROAS formula, step by step

The formula is simple: divide the revenue your ads generated by what you spent on them.

ROAS = attributed revenue ÷ ad spend

If you spend $1,500 on ads in a month and those ads bring in $6,000 of sales, your ROAS is 6,000 ÷ 1,500 = 4. Marketers write the same result in several ways: 4, 4:1, 4x or 400%. Google Ads uses the percentage form; its help page gives the example of $5 in sales for $1 of ad spend × 100% = a 500% target ROAS, and says you can find your historical figure by multiplying the "Conv. value/cost" column by 100. Meta and most store dashboards show a plain ratio such as 4.0. They all mean the same thing.

The hard part isn't the division. It's deciding what goes on each side of it.

What counts as revenue

Use the revenue you keep. That means the selling price after any discount codes, excluding sales tax, which belongs to the state, not to you. Our guide on how to calculate sales tax shows how to back tax out of a tax-included total. Shipping you charge the customer is part of revenue only if you also count the cost of shipping in your margin; be consistent.

Then think about returns and cancellations. Ad platforms record a conversion when the order is placed. If 10% of orders come back, a platform-reported ROAS of 4 is really about 3.6 on revenue you keep. For categories with heavy returns, such as clothing and shoes, recalculate ROAS once the return window has closed.

What counts as ad spend

At minimum, ad spend is what the platform charges you. For a true return, add the costs you incur only because you run the ads: agency or freelancer management fees, paid creative such as photography and video, influencer fees, and the share of any ad software you pay for. Platform-only ROAS is useful for comparing campaigns against each other. All-in ROAS is what tells you whether advertising pays.

Try it — your ROAS and break-even ROAS

Ad SpendRevenue from AdsGross Margin

Break-Even ROAS2.5×

Gross Profit after Ads₹900.00

StatusProfitable

ROAS4×

Open the full ROAS Calculator (PDF, save, compare)

Break-even ROAS: the number that matters

A ROAS of 4 sounds strong, but whether it makes money depends entirely on what each sale costs you to fulfil. Break-even ROAS is the ROAS at which the profit left from the sales exactly pays for the ads.

Break-even ROAS = 1 ÷ contribution margin (as a decimal)

Contribution margin is the share of each dollar of revenue left after every cost that rises with each order: the product itself (your cost of goods sold, including inbound freight, as the IRS defines it in Publication 334), packaging, outbound shipping, payment processing fees, marketplace commissions, and an allowance for returns and damaged goods. Rent, salaries and software subscriptions don't go in, because they don't change with one more order. Our contribution margin guide shows how to work it out line by line.

If your contribution margin is 40%, each $1 of sales leaves 40 cents to pay for ads and overheads. To cover $1 of ad spend, you need $2.50 of sales, so break-even ROAS is 1 ÷ 0.40 = 2.5. At a 25% margin it's 4.0; at 60% it's about 1.67. Low-margin businesses need much higher ROAS to make advertising pay.

Target ROAS for a profit goal

Breaking even isn't the goal; you also need ads to contribute to overheads and profit. If you want each ad-driven sale to leave a set percentage of revenue as profit after ad costs, use:

Target ROAS = 1 ÷ (contribution margin − target profit margin)

With a 40% contribution margin and a goal of keeping 10% of revenue after ads, target ROAS = 1 ÷ (0.40 − 0.10) = 3.33. That's the figure to enter as a target ROAS bid, or to judge campaigns against. The table above shows that as the target profit approaches your contribution margin, the ROAS you need climbs steeply, and a profit target equal to or above your margin can't be reached by ads at all.

Typical margins to sanity-check against

If you're not sure your margin is realistic, public-company data gives a rough check. NYU Stern's January 2026 dataset shows average gross margins of 33.18% for general retailers, 26.31% for grocery and food retail, 56.88% for apparel, 51.04% for household products and 32.24% for restaurants. These are gross margins for large listed companies, before shipping, card fees and returns, so a small online store's contribution margin is usually lower. Treat them as a ceiling, not a target.

Worked example: an online candle shop

A small candle company sells through its own website and runs Meta and Google ads. In September it spent $2,000 on ads, and the platforms attribute $8,000 of orders (after discount codes, excluding sales tax) to them. ROAS is 8,000 ÷ 2,000 = 4.0.

Now the costs per $100 of sales. Candles, jars, wicks and labels cost $30. Packaging and outbound shipping the shop pays for come to $12. Card processing is about $3. Refunds and breakage run at $3. That leaves a contribution margin of $52 on every $100, or 52%.

• Break-even ROAS: 1 ÷ 0.52 = 1.92.
• Contribution from the ad-driven sales: $8,000 × 0.52 = $4,160.
• Profit after ads: $4,160 − $2,000 = $2,160 toward rent, wages and profit.
• Marketing ROI: $2,160 ÷ $2,000 = 108%.

The owner also pays a freelancer $500 a month to manage the ads. All-in spend is $2,500, so all-in ROAS is 3.2 and profit after ads falls to $1,660, still comfortably above break-even. If she wanted every ad-driven sale to leave 20% of revenue as profit, her target ROAS would be 1 ÷ (0.52 − 0.20) = 3.13, so this campaign clears that bar on platform spend and barely clears it all-in. Our ROI guide covers the ROI side of this calculation in more depth.

How to calculate ROAS and decide if it's good enough

1. 1

   Pull revenue and spend for the same period

   Use revenue after discounts, excluding sales tax, and all ad costs for the same dates and campaigns.

2. 2

   Divide to get ROAS

   Revenue ÷ spend. Write it as a ratio (4.0) or multiply by 100 for Google's percent form (400%).

3. 3

   Work out contribution margin

   Price minus product cost, packaging, shipping, card or marketplace fees and returns, as a share of revenue.

   Contribution margin guide
4. 4

   Compare with break-even and target ROAS

   Break-even = 1 ÷ margin. Target = 1 ÷ (margin − profit goal). Above target: scale. Between: optimise. Below break-even: fix or pause.

5. 5

   Re-check after returns and with blended data

   Recalculate once the return window closes and compare with total revenue ÷ total ad spend.

ROAS vs ROI vs CAC vs ACoS vs MER

ROAS is one of several ad metrics, and each answers a different question. Using the candle shop's September numbers ($2,000 ad spend, $8,000 attributed revenue, 52% contribution margin and, say, 80 new customers) shows how they relate.

Ad metrics compared (candle shop, September)

Metric	Formula	Result	What it tells you
ROAS	Ad revenue ÷ ad spend	4.0 (400%)	Sales generated per ad dollar
Break-even ROAS	1 ÷ contribution margin	1.92	Minimum ROAS before ads lose money
Marketing ROI	(Contribution − ad spend) ÷ ad spend	108%	Profit return on the ad money
ACoS	Ad spend ÷ ad revenue × 100	25%	Share of revenue spent on ads (Amazon's measure)
CAC	Ad spend ÷ new customers	$25	Cost to win one new customer
MER / blended ROAS	Total revenue ÷ total ad spend	Depends on all sales	Whole-business return, including organic and repeat sales

ROAS

Formula

Ad revenue ÷ ad spend

Result

4.0 (400%)

What it tells you

Sales generated per ad dollar

Break-even ROAS

Formula

1 ÷ contribution margin

Result

1.92

What it tells you

Minimum ROAS before ads lose money

Marketing ROI

Formula

(Contribution − ad spend) ÷ ad spend

Result

108%

What it tells you

Profit return on the ad money

ACoS

Formula

Ad spend ÷ ad revenue × 100

Result

25%

What it tells you

Share of revenue spent on ads (Amazon's measure)

CAC

Formula

Ad spend ÷ new customers

Result

$25

What it tells you

Cost to win one new customer

MER / blended ROAS

Formula

Total revenue ÷ total ad spend

Result

Depends on all sales

What it tells you

Whole-business return, including organic and repeat sales

ROAS vs ROI. ROAS uses revenue; ROI uses profit. ROAS tells you how efficiently ads turn into sales, but only ROI, or ROAS compared with break-even, tells you whether they make money.

ROAS vs ACoS. Amazon sellers see ACoS, advertising cost of sales, instead. Amazon Ads defines it as ad spend ÷ ad revenue × 100, the inverse of ROAS, and notes that ACoS must be lower than your margin for ads to be profitable. A ROAS of 4 is an ACoS of 25%; a break-even ROAS of 2.5 is a break-even ACoS of 40%. If you also sell on Amazon, our guide on how to sell on Amazon covers the fees that go into that margin.

ROAS vs CAC. Customer acquisition cost divides ad spend by the number of new customers rather than by revenue. It matters most when customers buy again. If the candle shop's average customer places three orders over two years, the first order might only break even and the ad still pays off handsomely on the repeat orders. In that case, compare CAC with the contribution margin from a customer's lifetime of orders, not just the first one.

MER, or blended ROAS. The marketing efficiency ratio divides all revenue by all ad spend, across every channel. It ignores attribution entirely, which is its strength: it can't double count. If platform ROAS rises while MER falls, the platforms are claiming credit for sales that would have happened anyway.

Why your ROAS might be wrong: attribution

Every ROAS figure depends on attribution, the rules that decide which ad gets credit for a sale. Small changes in those rules can move ROAS a long way, so it helps to know the main traps.

Each platform grades its own homework. Google, Meta, TikTok and Amazon each count the sales they can link to their own ads. A customer who clicks a Google ad on Monday and a Meta ad on Wednesday, then buys, can be counted by both. Add up platform-reported revenue and it can exceed what your store actually sold.

View-through conversions inflate results. Some platforms count a sale if the buyer merely saw an ad and later bought, even without clicking. That captures some genuine influence, but it also credits ads for customers who were going to buy anyway, especially existing customers who see retargeting ads.

Analytics models changed. In Google Analytics 4, the rule-based first-click, linear, time-decay and position-based models were removed in November 2023. GA4 now offers data-driven attribution, paid and organic last click, and Google paid channels last click. Reports built on the old models won't match today's figures, so don't compare ROAS across that change without noting it.

Privacy rules hide some conversions. Since iOS 14.5, Apple's App Tracking Transparency framework requires apps to ask permission before tracking people across other companies' apps and websites, including for ad measurement. When users decline, platforms can't see every conversion directly and fill gaps with modelled estimates. Browser cookie limits and ad blockers have a similar effect on website tracking.

How to get closer to the truth

Pick one source of truth for decisions, usually your store or analytics data with a consistent attribution model, and use platform numbers only to compare campaigns within that platform. Track blended ROAS (MER) every month alongside it. When the two disagree sharply, trust the blended figure.

The most reliable test is incrementality: does the ad create sales that wouldn't otherwise happen? You can approximate it without special tools. Pause a campaign in some regions or for two weeks and watch total sales; hold out a slice of your customer list from retargeting and compare their purchase rate with those who saw the ads. If sales barely move when an ad stops, its reported ROAS was mostly credit for existing demand.

A simple holdout test

Step 1

Pick one campaign

Step 2

Pause it in half your regions

or for 2 weeks

Step 3

Compare total sales in both halves

Step 4

Incremental ROAS

extra sales ÷ spend

For automated bidding, data volume matters too. Google says Search and Shopping campaigns need at least 15 conversions in the past 30 days to use target ROAS bidding. With fewer conversions, the system has little to learn from and results swing from week to week, so small accounts are often better off with simpler bidding until volume builds.

Measuring ROAS for offline and local ads

ROAS isn't only for online stores. A restaurant running a mailer, a contractor buying local radio or a salon sponsoring a school event can calculate it too, as long as it can link sales to the ad. Use a unique promo code or offer for each campaign, a separate tracked phone number, a dedicated landing page or QR code, and a "how did you hear about us?" question at checkout or booking. The SBA's marketing guidance makes the same point: compare marketing costs with the revenue they generate, using consistent measurement even for hard-to-track tactics such as print or word of mouth.

For service businesses, revenue per job is often large and lumpy. A roofer who spends $1,200 on local ads and books two jobs worth $18,000 has a ROAS of 15, but with a 30% contribution margin after materials and crew labor, profit after ads is $4,200. One more or one fewer job changes the picture dramatically, so look at ROAS over a quarter rather than a single month.

If you pay influencers or offer free products for reviews, include that cost in ad spend, and follow the FTC's rules on disclosing material connections. The FTC's Endorsement Guides, revised in 2023, and its rule on consumer reviews and testimonials apply to small businesses as much as big brands.

Common ROAS mistakes and how to fix them

Comparing ROAS without knowing your margin. A 3.0 ROAS can be excellent for a 60%-margin business and loss-making for a 25%-margin one. Always set ROAS next to break-even ROAS.

Including sales tax in revenue. It inflates ROAS by your tax rate. Pull revenue excluding tax from your store or accounting system.

Ignoring returns and cancellations. Recalculate ROAS after the return window, or apply your average return rate to platform revenue.

Leaving out management and creative costs. Platform-only ROAS is fine for comparing ads; all-in ROAS is the one that tells you whether advertising pays.

Summing platform ROAS. Add up the revenue each platform claims and you'll usually count some orders twice. Use blended ROAS for the total.

Chasing ROAS instead of profit. Pushing ROAS higher often means cutting spend to only the most certain buyers, which can shrink total profit. The best budget is the one that maximises profit after ads, which may be a lower ROAS on a larger spend, as long as each extra dollar still clears break-even.

Monthly ROAS review

0/7

• Revenue excludes sales tax and reflects discounts and returns
• Ad spend includes platform, agency, creative and influencer costs
• Contribution margin updated for current product, shipping and fee costs
• Break-even and target ROAS written down for each product line
• Platform ROAS compared with blended ROAS (MER)
• Attribution model and window unchanged since last month, or change noted
• At least one holdout or pause test run this quarter

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Official and platform references

• Google Ads — About Target ROAS biddingROAS as a percent, conversion requirements
• Google Analytics — Attribution settingsAvailable models and lookback windows
• Amazon Ads — ACOS guideACOS formula and relation to ROAS
• Apple — User privacy and data useApp Tracking Transparency
• SBA — Marketing and salesBudgeting and measuring marketing returns
• FTC — Endorsements, influencers and reviewsDisclosure rules for paid promotion

What to do next

Work out your contribution margin first, because every ROAS decision depends on it. Then use the ROAS calculator to set break-even and target ROAS for each product line, and compare them with last month's results. If you're pricing products as well, our guide on how to calculate markup shows how price changes move your margin, and with it the ROAS you need. For a fuller view of whether marketing pays, see how to calculate ROI.

Frequently asked questions

What is the formula for ROAS?

ROAS = revenue attributed to ads ÷ ad spend. If $1,500 of ads brings in $6,000 of sales, ROAS is 6,000 ÷ 1,500 = 4, written as 4:1, 4x or 400%. Use revenue before sales tax and after discounts and refunds, and include every cost of running the ads, such as agency or software fees, in the spend.

How do I calculate break-even ROAS?

Divide 1 by your contribution margin as a decimal. Contribution margin is the share of each sale left after product cost, shipping, payment fees, returns and other costs that rise with each order. With a 40% margin, break-even ROAS is 1 ÷ 0.40 = 2.5. Below 2.5 the ads lose money; above it they add profit.

What is a good ROAS?

There's no universal number, because it depends on your margin. A store with a 60% contribution margin breaks even at about 1.7, while one with a 25% margin needs 4.0 just to break even. A good ROAS is one above your break-even point by enough to cover the profit you want, measured over a period long enough to include returns.

What's the difference between ROAS and ROI?

ROAS uses revenue; ROI uses profit. ROAS of 4 means $4 of sales per $1 of ads. ROI subtracts the cost of those sales: if the $4 of sales leaves $1.60 of contribution, ROI on the $1 of ads is ($1.60 − $1) ÷ $1 = 60%. A campaign can show a healthy-looking ROAS and still have a negative ROI.

Is ROAS the same as ACoS?

They're inverses. Amazon's ACoS (advertising cost of sales) is ad spend ÷ ad revenue × 100, so a ROAS of 4 is an ACoS of 25%. Amazon Ads notes that to stay profitable your ACoS must be lower than your margin, which is the same test as ROAS being higher than break-even ROAS.

Why does my ad platform show a higher ROAS than my store?

Each platform counts the sales it can link to its own ads, including some customers who saw an ad but would have bought anyway, and two platforms can both claim the same order. Privacy limits such as Apple's App Tracking Transparency also force platforms to model some results. Compare platform ROAS with blended ROAS: total revenue ÷ total ad spend.

Sources & verification

Figures on this page were checked against the sources below when it was last reviewed on 9 October 2026. Each rate and limit is stored once with its own official source and review date, and official update channels are monitored daily so changes are picked up. How we verify

1. 1.About Target ROAS bidding — Google Ads Help · accessed 9 October 2026
2. 2.Select attribution settings — Google Analytics Help · accessed 9 October 2026
3. 3.User privacy and data use (App Tracking Transparency) — Apple Developer · accessed 9 October 2026
4. 4.What is ACOS? Advertising cost of sales — Amazon Ads · accessed 9 October 2026
5. 5.Marketing and sales — U.S. Small Business Administration · accessed 9 October 2026
6. 6.Publication 334 (2025), Tax Guide for Small Business — IRS · accessed 9 October 2026
7. 7.Endorsements, Influencers, and Reviews — Federal Trade Commission · accessed 9 October 2026
8. 8.Margins by sector (US), January 2026 — NYU Stern (Aswath Damodaran) · accessed 9 October 2026