Glossary
Attribution Window
An attribution window is the period after a click during which a purchase still counts as yours. It is also called a cookie window.
What it means
When a reader clicks your affiliate link, the merchant's system records the click — usually with a browser cookie — together with the time. If the reader buys within the window, the sale is attributed to you and you earn the commission; if they buy after the window has closed, you earn nothing. Windows vary widely by programme: some last a day, some 30 days, some 90. The length is set by the merchant or the affiliate programme, published in the programme's terms, and it can change. A long window does not mean a generous programme, and a short window does not mean a bad one — the window is one term among many, and a programme with a long window and a low commission may pay less than a programme with a short window and a high one.
Example
As an illustration, suppose a programme has a 30-day window. A reader clicks your link on day 1, thinks it over, and buys on day 20: the sale is yours, and the commission is paid. If the same reader buys on day 31, the window has closed and the commission is not yours, even though your link was the one they first clicked. And if the reader clicks a second affiliate's link on day 25, most programmes give the sale to the most recent click — which is why the last click, not the first, usually wins.
Common misunderstandings
The most common misunderstanding is that the window starts when the reader buys. It starts when they click. The second is that a cookie guarantees attribution: cookies are cleared, browsers block them, readers switch devices, and a purchase on a phone after a click on a laptop may never be linked to your click at all. Attribution is an approximation, not a record of who really did the persuading.
Related terms
Learn more
- How Affiliate Marketing Works
- Affiliate Disclosure Requirements
- Conversion Optimization for Affiliates
- Affiliate Conversion Calculator
- Affiliate Marketing Fundamentals
- Back to the full glossary
Last checked: 14 November 2026.
Frequently asked questions
What is an attribution window?
The period after a click during which a purchase still counts as yours. A 30-day window means a purchase on day 20 earns the commission, and a purchase on day 31 does not.
When does the window start?
When the reader clicks, not when they buy. The click is recorded, with its time, and the window runs from that moment.
What happens if the reader clicks two affiliates' links?
Most programmes give the sale to the most recent click — the last click usually wins, not the first.
Does a cookie guarantee I get the commission?
No. Cookies are cleared, browsers block them, and a purchase on another device may never be linked to the click. Attribution is an approximation.