Break-even ROAS: the one number to know before you spend on ads

The short answer

ROAS, return on ad spend, is the revenue an ad platform credits to your ads divided by what the ads cost. A ROAS of 4× means €4 of sales for every €1 spent. On its own it says nothing about profit, because €4 of sales can leave you €2 or €0.40 depending on what the goods cost you.

Break-even ROAS is the point where the margin on those sales exactly pays for the ads. If each euro of revenue leaves you 40 cents after product, postage and fees, you need €2.50 of revenue to cover €1 of ads. That is 1 ÷ 0.40 = 2.50×. Below that line every sale bought with ads costs you money; above it, the ads are paying their way.

What counts as margin

The number only works if the margin is honest. Use the share of each order, excluding VAT, that is left after every cost that grows with the order:

• Product cost, landed: purchase price plus inbound freight and duty.
• Shipping you pay, minus what the customer pays you for it.
• Payment fees, as a percentage plus any fixed fee per order.
• Packaging and picking, if you pay a warehouse per order.

Leave out the ad spend itself, because that is what you are solving for, and leave out fixed costs such as rent, software and salaries. Those are paid from the profit, which is why a target above break-even matters.

The formula, with a worked example

# all values excl. VAT, margin and profit as decimals
break_even_roas = 1 / margin
target_roas     = 1 / (margin - target_profit)
max_cost_order  = net_order_value * (margin - target_profit)

Take a fictional shop selling wool socks. An average order is €50.00 excluding VAT. Socks, packaging, postage and the payment fee come to €30.00, so the margin is €20.00, or 40 %.

1. Break-even ROAS: 1 ÷ 0.40 = 2.50×. The most an order can cost in ads before it loses money is €20.00.
2. The owner wants 10 % of each order as profit, €5.00. Target ROAS: 1 ÷ (0.40 − 0.10) = 3.33×.
3. Maximum cost per order at that target: €50.00 × 0.30 = €15.00.

VAT and refunds change the number the platform shows

VAT. VAT is collected for the tax office, so it never pays for ads. If your shop sends order values including VAT to Google Ads or Meta, every ROAS on screen reads higher than the money you keep, by exactly 1 + the VAT rate. At the Finnish standard rate of 25.5 %, a 2.50× break-even shows up in the platform as 2.50 × 1.255 = 3.14×, and the 3.33× target becomes 4.18×.

Refunds. The platform counts a sale when it happens and does not take it back when the goods are returned. If 10 % of tracked revenue is refunded, divide by 0.90: break-even rises from 2.50× to 2.78×. With VAT-inclusive values and 10 % refunds together, it is 1.255 ÷ (0.40 × 0.90) = 3.49×.

That assumes returned goods go back into stock. Return postage and damaged items push the number higher still. How VAT on the ad spend itself is handled depends on your registration; confirm with your accountant.

Break-even ROAS by margin

The same sum for common margins, so you can read off your line. The row nearest the margin in the box above is highlighted.

Three ways the number goes wrong

A margin that forgets the postage

Product cost alone flatters the margin. A shop that calls itself 50 % margin may be nearer 38 % once postage and payment fees are in, and its real break-even is 2.63×, not 2.00×. Campaigns that looked profitable at 2.3× were losing money all along.

Two platforms, two bases

If Google Ads receives values with VAT and Meta receives them without, their ROAS figures cannot be compared, and one of them is judged against the wrong line. Pick one basis and send it everywhere; tracking set-up fixes this at the source.

One average for every product

A store-wide margin hides the spread. If socks earn 60 % and boots 25 %, their break-even points are 1.67× and 4.00×. Under one shared target, the platform happily spends on the boots. Splitting products by margin in Shopping and Performance Max keeps each group on its own line.

What to do next

1. 1Work out your own number

   Enter your margin, order value and profit target in the break-even ROAS and CPA calculator. It takes a minute and nothing is sent anywhere.

2. 2Make the platform report the right revenue

   One basis, net or gross, on every platform, with refunds fed back where you can. See GA4, GTM and server-side tracking.

3. 3Set targets per margin group, or have it done

   Use target ROAS in Shopping and Performance Max, and cut what stays below the line. Paid ads management starts from exactly this number.