How to Calculate Break-Even ROAS for Ecommerce (Formula + Calculator)

What break-even ROAS means

Break-even ROAS is the minimum revenue-to-ad-spend ratio at which an order covers its variable costs and the advertising used to acquire it. It is not a universal benchmark: every store has a different product cost, fulfillment cost, payment fee, refund rate and margin structure.

There are two decisions hiding under the same phrase. Order-level break-even ROAS asks whether one acquired order can pay for its own variable costs and ad spend. Commercial break-even asks how much the whole business can spend after fixed costs, organic revenue and the share of revenue actually coming from paid media. The second number should not replace the first.

The break-even ROAS formula and the maximum CPA

First calculate contribution before advertising: revenue or AOV − product cost − fulfillment − payment and platform fees − other variable costs. Divide that amount by revenue to get the contribution margin before ads.

Order-level break-even ROAS = revenue ÷ contribution before ads = 1 ÷ contribution margin. The maximum CPA at zero contribution is the contribution before ads itself. If you require a target profit margin, target maximum CPA = contribution before ads − (revenue × target profit margin).

Worked ecommerce example

Suppose an order sells for $60. Product cost is $18, fulfillment is $7, payment and platform fees are $2, and the refund reserve is $1. Contribution before advertising is $32, or 53.3% of revenue.

Break-even ROAS is therefore $60 ÷ $32 = 1.88×. At a 2.5× ROAS, the campaign spends $24 to generate $60 of revenue, leaving $8 of contribution after advertising before fixed overhead. The waterfall below shows the same logic in order rather than hiding it inside a single ratio.

Low-, mid- and high-margin scenarios

The same $60 AOV can require very different ad performance. The table assumes a 10% target profit margin and keeps fixed costs outside the order-level calculation.

Max ad budget, commercial ROAS and target ROAS

A per-order ROAS floor does not tell you how much the business can spend in a month. For a simple commercial planning view, maximum ad budget at zero profit = (monthly revenue × contribution margin) − fixed costs. If only part of revenue is paid-attributed, commercial ROAS floor = paid-attributed revenue ÷ maximum ad budget.

For a target profit margin, target maximum ad budget = monthly revenue × (contribution margin − target profit margin) − fixed costs. If this is negative, the business cannot fund the target at that revenue and margin level, even before increasing spend.

How to use the number on Meta, Google and TikTok

Use the order-level result as an internal guardrail and the commercial result as a budget-capacity check. None of the platforms automatically knows your true COGS, refund reserve, inventory cash needs or fixed overhead unless you deliberately send a different conversion value and maintain that measurement system.

Costs and edge cases that change the answer

• Product cost or cost of goods sold.
• Fulfillment, shipping and packaging that scale with the order.
• Payment, platform and marketplace fees.
• A realistic refund, return, tax or discount reserve when it materially affects contribution. Decide whether the calculation is before or after VAT/sales tax and use the same basis for revenue and costs.
• Blended AOV can hide a low-margin SKU. Calculate by product or contribution tier when paid traffic is concentrated on specific offers.
• Fixed costs are important for net profit and break-even units, but keep them separate from the per-order contribution margin used for order-level break-even ROAS.
• Cash timing can be tighter than accounting profit: inventory is paid before the order, payment processors settle later and refunds may arrive after the ad spend.