Affiliate Commission Calculator
What an affiliate programme earns and costs — commission per sale, the margin left, and the incremental sales it needs to be worth running.
Commission is a share of order value, so it comes straight out of gross margin.
How the affiliate commission calculator works
Commission is a share of order value, so it comes straight out of gross margin. A 10% commission on a 40% margin business takes a quarter of the margin.
The number that decides whether the programme works is incrementality: what share of the attributed sales would have happened anyway. Affiliates often sit last in the path on sales already won, and paying commission on those is pure margin loss.
Formula: net margin = order value × (margin − commission rate)
Worked examples
| Inputs | Monthly net contribution | Note |
|---|---|---|
| 10% commission on a 40% margin | 6,940 | a quarter of the margin |
| Low incrementality | -2,020 | the programme turns negative |
| A thin margin | -1,460 | commission takes two thirds of it |
FAQFrequently asked questions
How much commission should I pay?
Whatever leaves an acceptable margin after the cost of goods. The break-even row shows the ceiling at your incrementality.
What is incrementality?
The share of attributed sales that would not have happened without the affiliate. It is the single most important number here and the hardest to measure.
Why do coupon affiliates cause trouble?
Because they often intercept customers already at checkout. The sale was won; the commission is pure margin loss.
How do I measure incrementality?
Holdout tests — suspend the affiliate in some regions or periods and compare. It is disruptive and it is the only reliable method.
Is affiliate cheaper than paid ads?
Per sale, usually, because you only pay on conversion. Per incremental sale, often not, once low-incrementality traffic is accounted for.
Where these figures come from
- Interactive Advertising Bureau — measurement guidelines — the impression and viewability definitions CPM depends on
- Advertising Standards Authority — the UK advertising regulator
Last checked: September 2026. These are standard industry definitions; where platforms disagree, the page says so.