Short answer: To calculate ROAS, divide the revenue your ads generated by what you spent on those ads. $10,000 in revenue from $2,500 in spend is a ROAS of 4, often written as 4x or 400%. To know whether that's profitable, compare it with your break-even ROAS: 1 divided by your gross margin. With a 50% margin, you break even at a ROAS of 2.

The ROAS calculation itself takes ten seconds. The harder part is knowing which revenue to put in, which spend to divide by, and what number you actually need to hit. A ROAS of 3 can mean a healthy campaign for one store and a slow leak for another.

This guide walks through the ROAS formula with examples, gives you a free calculator for both ROAS and break-even ROAS, and explains the difference between blended ROAS and the ROAS each ad platform reports. It ends with the catch that most ROAS guides skip: your ROAS is only as accurate as the conversions your tracking counts.

The ROAS Formula

ROAS stands for return on ad spend. It tells you how much revenue comes back for every dollar you put into ads.

ROAS = revenue from ads ÷ ad spend

You'll see it written three ways, and they all mean the same thing:

• As a ratio: 4:1

• As a multiple: 4x, or just 4

• As a percentage: 400%

Google Ads uses the percentage version. Its target ROAS bidding guide gives the example of $5 in sales for $1 in ad spend, which works out to a 500% target ROAS. Meta Ads Manager shows the multiple (purchase ROAS of 4.00, for example). Same math, different label.

ROAS is one of three related metrics. MER and CAC look at the business as a whole, while ROAS looks at a single channel, campaign or ad. Our glossary has a short comparison of ROAS, CAC and MER.

How to Do a ROAS Calculation Step by Step

Here's how to calculate ROAS for one campaign without fooling yourself along the way.

1. Pick the scope and the period. One campaign, one ad set or one channel, over a fixed date range. A week or a month is more useful than a single day, because daily numbers swing with paydays and weekends.

2. Get the revenue your ads drove. In practice that's the conversion value the ad platform attributes to the campaign. Note the attribution window it uses, because that decides which sales get counted (more on this below).

3. Get the ad spend for the same scope and period. Use the spend the platform reports. If you want a stricter number, add creative production or agency fees, but be consistent so you can compare periods.

4. Divide revenue by spend.

Worked example: Your Meta prospecting campaign spent $4,000 last month. Ads Manager attributes 95 purchases worth $13,600 to it.

ROAS = 13,600 ÷ 4,000 = 3.4

For every dollar spent, $3.40 in revenue came back. Whether that's good depends on your margin, which is where break-even ROAS comes in.

Free ROAS and Break-Even ROAS Calculator

Fill in your revenue and ad spend to get your ROAS. Add your average order value, product cost and fees to see your break-even ROAS and the most you can pay in ads per order.

How to Calculate Break-Even ROAS

Break-even ROAS is the ROAS at which your ad spend eats up your entire gross margin. At that point every order your ads bring in pays for the product, the shipping, the fees and the ad, and leaves nothing over. Above it, ads add profit. Below it, you lose money on every order they drive.

Break-even ROAS = 1 ÷ gross margin

Gross margin here means what's left of each dollar of revenue after the variable costs of an order:

• Cost of goods sold (COGS): what the product costs you

• Shipping and fulfilment: the part you pay, not what the customer pays

• Payment and platform fees: card fees, Shopify Payments, marketplace fees

• Other variable costs per order: packaging, returns allowance

Leave ad spend out. That's what break-even ROAS is measuring against.

Worked example: Your average order is $80. Product cost is 35% of the order value and shipping plus fees take another 15%. That leaves a gross margin of 50%.

Break-even ROAS = 1 ÷ 0.50 = 2.0

So the Meta campaign above, at a ROAS of 3.4, clears break-even comfortably. The calculator also shows the maximum ad cost per order: $80 × 50% = $40. If you pay more than $40 in ads to win an $80 order, that order loses money.

Here's how quickly break-even ROAS climbs as margins shrink:

Discounts hit this hard. If that $80 product goes on sale for 25% off, it sells for $60 while your costs stay about $40, so your margin drops to roughly 33% and your break-even ROAS rises to about 3. Run the calculator again before every big promotion.

Break-Even ROAS vs Target ROAS

Break-even is the floor. Your target ROAS sits above it, by enough to cover fixed costs like salaries, software and rent, plus the profit you want to keep.

How far above depends on what you're optimizing for. A store chasing growth may run prospecting campaigns close to break-even, because some of those new customers will order again. A store focused on cash flow will want a wider gap. If you're wondering what number to aim for, we cover that in what is a good ROAS, with published benchmarks per platform.

If your margins differ a lot between products, ROAS can mislead you. A campaign selling low-margin bestsellers can show a higher ROAS than one selling high-margin items and still make less money. That's what POAS (profit on ad spend) fixes, and we show how to see it in our guide to POAS and new vs returning customers in TikTok.

Blended ROAS vs Platform ROAS

Everything above is platform ROAS: one platform's attributed revenue divided by spend on that platform. There's a second version you'll hear about.

Blended ROAS = total store revenue ÷ total ad spend across every channel

Blended ROAS is the same thing as MER, the marketing efficiency ratio. It uses your Shopify revenue and your total ad spend, so it doesn't depend on which platform claims which sale.

The two answer different questions:

• Platform ROAS tells you which campaign, ad set or creative to scale or cut. Use it inside Meta, Google, TikTok and Pinterest.

• Blended ROAS tells you whether your marketing as a whole pays for itself. Use it at store level, weekly and monthly.

One rule matters here: never add platform ROAS figures together. A shopper might see a TikTok video, click a Meta ad and buy through a Google search. All three platforms can count that order as theirs. Add up what each one reports and you'll often get more revenue than your store actually made. Blended ROAS counts each order once.

Break-even works the same way at store level. Your break-even blended ROAS is also 1 ÷ gross margin, which makes it a useful sanity check: if your blended ROAS sits below break-even while every platform reports a healthy ROAS, the platforms are overlapping.

The Catch: ROAS Is Only as Accurate as the Conversions You Count

The formula is simple. The revenue you feed into it isn't.

Platform ROAS depends on the conversions the platform actually sees, and browser pixels miss around 30-60% of conversions. Ad blockers stop the pixel from loading, Safari's tracking prevention shortens cookie lifetimes, iOS privacy settings limit what apps can track, and consent banners keep some visitors out of client-side tracking altogether. Every sale the pixel misses is revenue left out of your ROAS calculation.

That causes three problems:

• Your ROAS looks lower than it is, so you may pause campaigns that were actually profitable.

• The platform's bidding learns from a partial picture. Meta and Google optimize toward the buyers they can see, which is a smaller, skewed slice of your real customers. Read more about this in why AI bidding needs better data.

• Platforms can disagree with Shopify by a lot, in both directions, because one platform misses sales while another claims shared ones.

Attribution windows add another layer. By default, Meta counts a purchase within 7 days of a click or 1 day of a view, while Google Ads uses a 30-day click window by default. The same campaign can show a different ROAS depending only on the window, so always compare like with like.

The fix is to send conversions from your server as well as the browser. With server-side tracking, the purchase is recorded in Shopify and sent straight to each platform through its own API, so ad blockers and browser limits don't stop it. TrackBee does this for Meta, Google, TikTok, Pinterest, GA4 & Klaviyo, deduplicates it against the pixel and enriches it with first-party data, so each platform can match more purchases to the right ad. If your platforms report fewer sales than Shopify, start with our guide to fixing underreported conversions on Shopify.

Want to see which channels really drive your sales, without the double counting? That's what ecommerce attribution in TrackBee is for: one view of every channel's contribution, based on your Shopify orders.

Frequently Asked Questions

How do you calculate ROAS?

Divide the revenue from your ads by the amount you spent on them. $12,000 in revenue from $3,000 in ad spend gives a ROAS of 4, also written as 4x, 4:1 or 400%.

What is the formula for break-even ROAS?

Break-even ROAS = 1 ÷ gross margin, where gross margin is revenue minus product cost, shipping, fees and other variable costs per order, as a share of revenue. With a 40% gross margin, your break-even ROAS is 2.5.

Is ROAS the same as ROI?

No. ROAS compares revenue with ad spend only. ROI compares profit with your total investment, including product costs and overheads. A campaign can have a ROAS of 3 and still lose money if your margins are thin.

What is blended ROAS?

Blended ROAS is your total store revenue divided by your total ad spend across all channels. It's another name for MER (marketing efficiency ratio). Because it uses your own revenue, platforms can't double-count sales in it.

How do you convert ROAS to a percentage?

Multiply it by 100. A ROAS of 3.5 is 350%. Google Ads shows ROAS as a percentage, while Meta Ads Manager shows it as a multiple.

Why is my ROAS different in Meta, Google and Shopify?

Each platform uses its own attribution window and only counts the conversions it can see. Browser pixels miss around 30-60% of conversions, while overlapping platforms can claim the same order. Shopify counts every order once but doesn't know which ad drove it.

Calculate ROAS on Numbers You Can Trust

The ROAS formula is easy. Getting the revenue right is the hard part. TrackBee sends every Shopify purchase to your ad platforms server-side, so your ROAS reflects the sales that actually happened. Try TrackBee for free and compare the numbers yourself.