Break-even 8 min read

Break-even in ecommerce with paid advertising: from theory to practice

Break-even is not just a theoretical concept. Used correctly, it determines your minimum ROAS targets, helps you validate budgets before launching, and tells you when a campaign structure needs fixing rather than pausing.

Calculate my break-even point

Break-even is the floor, not the target

The most common mistake is treating break-even as the goal. Break-even means ROI = 0%. You cover all costs but generate no profit. For a business to be healthy, campaigns need to perform significantly above break-even.

Break-even is the floor. Real targets live above it.

A campaign running exactly at break-even ROAS generates zero profit. Any operational hiccup (higher returns one week, CPM spike) pushes it into loss. Set actual targets 30–50% above break-even ROAS.

Setting tROAS targets from break-even

Your minimum profitable ROAS = 1 ÷ gross margin. Use this as the starting point for tROAS bidding. Set your actual tROAS target at ×1.4 the minimum to account for attribution inflation and ensure real profit.

Gross marginMin. ROAS (break-even)Recommended tROAS (×1.4 buffer)
25%4.0x5.6x
30%3.33x4.67x
40%2.5x3.5x
50%2.0x2.8x

The ×1.4 multiplier accounts for: attribution window inflation (platforms claim 20–40% more sales than they actually generated), return rate impact, and provides a meaningful ROI buffer above break-even.

Budget reality check before launching

Before setting a budget, calculate how many sales you need at break-even and whether your budget realistically allows reaching that number based on historical conversion rates and CPC.

Example budget check: is £1,000 enough?

Budget£1,000
AOV£65
Gross margin38%
Contribution per sale (£65 × 38%)£24.70
Break-even sales needed (£1,000 ÷ £24.70)41 sales
At 1.5% conversion rate: clicks needed (41 ÷ 0.015)2,733 clicks
At £0.80 average CPC: budget needed (2,733 × £0.80)£2,186
Verdict£1,000 is insufficient — need £2,200+

This analysis reveals three paths: increase budget to £2,200+, improve conversion rate to 2.8%+ (41 sales ÷ 1,467 clicks at £0.80 CPC = fits in £1,000), or increase AOV to reduce required sales count.

Deriving maximum CPA from break-even

Break-even logic directly gives you the maximum CPA you can pay: Max CPA = AOV × gross margin.

ROI at different ROAS levels (38% margin)

ROAS 2.0x (£65 AOV) ROI −47%
ROAS 2.63x (break-even) ROI 0%
ROAS 3.5x (tROAS target) ROI +33%

Use this to set a target CPA at 80% of maximum (Max CPA × 0.8). This leaves a safety buffer and accounts for CPA volatility. If your Max CPA is £24.70, your target CPA should be ~£20.

Returns adjustment

If you have 10% returns, multiply your break-even sales target by 1.1 and reduce effective margin by the same factor. A 38% gross margin with 10% returns works out to ~34% effective margin for break-even calculations.

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