Quick answer: break-even ROAS = 1 ÷ gross margin, where gross margin is what is left of each sale after every cost that scales with the order (product, shipping, payment fees, returns) — but before ad spend. At a 40% margin you need 2.5x ROAS to break even; at 20% you need 5x. Below that number every ad sale loses money, however good the ROAS looks.
If you just want the number, use the break-even ROAS calculator. This guide shows how the calculation works, what to put into “margin” so the answer is honest, and five worked examples you can copy.
The break-even ROAS formula
ROAS (return on ad spend) is revenue from ads divided by ad spend. Break-even is the point where the gross profit from those sales exactly pays for the ads. Since gross profit = revenue × margin, break-even happens when revenue × margin = ad spend, which rearranges to:
Break-even ROAS = 1 ÷ gross margin
| Gross margin | Break-even ROAS | Break-even ACOS |
|---|---|---|
| 70% | 1.43x | 70% |
| 60% | 1.67x | 60% |
| 50% | 2.00x | 50% |
| 40% | 2.50x | 40% |
| 30% | 3.33x | 30% |
| 25% | 4.00x | 25% |
| 20% | 5.00x | 20% |
| 15% | 6.67x | 15% |
ACOS (advertising cost of sale, the Amazon metric) is the same relationship upside down: ad spend ÷ revenue. Break-even ACOS always equals your gross margin.
Step 1: work out the right margin
Most wrong break-even numbers come from using product margin alone. Subtract every cost that rises with each order:
- Cost of goods (what the product costs you landed)
- Shipping and packaging you pay for
- Payment processing fees (typically 2–3% plus a fixed fee per order)
- Marketplace or platform fees charged per sale
- Returns and refunds, as an average allowance per order
- Pick, pack and fulfilment fees
Do not subtract fixed overheads (rent, salaries, software subscriptions) or the ad spend itself. Those are paid from the profit above break-even. Some teams call this figure contribution margin; for this calculation it is the same thing.
Gross margin = (order value − variable costs per order) ÷ order value
Step 2: worked examples
Example 1: apparel store, $50 order
- Cost of goods $20, shipping $5, payment fees $1.50, returns allowance $2.50 = $29 variable cost
- Margin = ($50 − $29) ÷ $50 = 42%
- Break-even ROAS = 1 ÷ 0.42 = 2.38x
- Maximum you can pay to win one order (max CPA) = $50 × 42% = $21
Using product margin alone ($30 of $50, or 60%) would have given 1.67x — and every campaign between 1.67x and 2.38x would have looked profitable while losing money.
Example 2: skincare brand, $40 order
- Cost of goods $8, shipping $4, payment fees $1.20 = $13.20 variable cost
- Margin = $26.80 ÷ $40 = 67%
- Break-even ROAS = 1.49x; max CPA = $26.80
High-margin products can profit at a ROAS that would sink a low-margin store. That is why “a good ROAS is 4x” is not a useful rule.
Example 3: electronics, $200 order
- Cost of goods $150, shipping $10, payment fees $6 = $166 variable cost
- Margin = $34 ÷ $200 = 17%
- Break-even ROAS = 5.88x; max CPA = $34
Thin-margin categories need very high ROAS on the first order, which is why they lean on repeat purchases (see example 5).
Example 4: adding a profit target
Break-even means zero profit. To keep a profit margin after ads, subtract it before inverting:
Target ROAS = 1 ÷ (gross margin − desired profit margin)
For the apparel store (42% margin) wanting 10% profit: 1 ÷ (0.42 − 0.10) = 1 ÷ 0.32 = 3.13x. If the desired profit is equal to or higher than the margin, no ROAS can deliver it — the price or the costs have to change.
Example 5: subscription or repeat buyers (lifetime value)
A coffee subscription sells for $30 a month at a 50% margin, and the average customer stays for 4 orders.
- First-order break-even ROAS = 1 ÷ 0.50 = 2.0x (max CPA $15)
- Lifetime gross profit = $30 × 50% × 4 = $60, so you can pay up to $60 to acquire a customer and still break even over their lifetime
- Measured on the first $30 order, that is a break-even ROAS of $30 ÷ $60 = 0.5x
Bidding to a lifetime break-even lets you outbid competitors, but you carry the cost until the repeat orders arrive — and the “4 orders” must come from your own retention data, not hope. Check the ratio with the CAC to LTV calculator.
How to calculate actual ROAS (and compare it)
ROAS = revenue attributed to ads ÷ ad spend. $12,000 of revenue from $4,000 of spend is 3x (or 300%). Compare it with your break-even: at a 42% margin (2.38x), 3x is profitable; at a 25% margin (4x), it is a loss. The ROAS calculator does both in one step.
Platform-reported ROAS is only as good as attribution. Tag every non-platform link with UTM parameters (our UTM builder does it in seconds) so revenue in your analytics lines up with spend. Many teams also track MER (marketing efficiency ratio = total revenue ÷ total marketing spend) as a cross-check that does not depend on any one platform’s attribution.
Common mistakes
- Using product margin only. Shipping, fees and returns can take 10–20 points of margin, which moves break-even a long way (example 1).
- Including fixed costs. Rent and salaries do not scale with each extra ad sale; including them makes break-even look harder than it is.
- Using revenue including tax. Use net revenue, after sales tax or GST/VAT and discounts.
- One break-even for the whole catalogue. Products with different margins need different targets; set them per product group or campaign.
- Trusting a lifetime value you have not measured. LTV-based targets only work with real repeat-purchase data.
Where email fits
Paid ads usually win the first order; email wins the second, third and fourth. Every repeat order you earn through welcome, post-purchase and win-back emails raises lifetime value — which, as example 5 shows, lowers the ROAS you need on acquisition. Estimate what your list is worth with the email ROI calculator, and start with a post-purchase or win-back template.
FAQ
What is a good ROAS?
Any ROAS above your break-even ROAS, and ideally at or above your target ROAS. 4x is often quoted, but it is loss-making at a 20% margin and very profitable at a 60% margin.
How do I calculate break-even ROAS from a percentage margin?
Convert the margin to a decimal and divide 1 by it: 35% becomes 0.35, and 1 ÷ 0.35 = 2.86x. Or divide 100 by the percentage: 100 ÷ 35 = 2.86.
What is the difference between ROAS and ROI?
ROAS is revenue per ad dollar; ROI is profit per dollar after all costs. A campaign can have a 3x ROAS and a negative ROI if margins are thin.
Is break-even ACOS the same as break-even ROAS?
They describe the same point from opposite sides. Break-even ACOS = your gross margin (for example 40%); break-even ROAS = 1 ÷ that margin (2.5x).
Should I bid to first-order or lifetime break-even?
Bid to first-order break-even until you have reliable repeat-purchase data and the cash to wait for it. Then you can move towards a lifetime target, product line by product line.