How Long Should Affiliate Cookies Last? Picking a Referral Window That's Actually Fair

A customer clicks a partner's link on Tuesday, thinks about it, and buys three weeks later. Whether that partner earns anything depends on one number in your settings: the cookie duration, also called the referral or tracking window. It's the single setting partners check before joining a program — and one of the easiest to get wrong in both directions.

What the window really represents

The cookie window is your answer to a fairness question: how long after a recommendation is a sale still because of that recommendation? A one-day window says "only if you buy immediately." A one-year window says "forever, basically." Neither matches how people shop. The honest answer sits wherever your customers' consideration time sits.

So start with your own data, not industry folklore. Your analytics or order history will show the typical gap between a first visit and a purchase. Products under $50 mostly close within days; a $400 course or an annual membership routinely takes weeks of mulling. Set the window comfortably above your typical consideration time — if most delayed purchases land within three weeks, a 30-day window credits nearly all of them.

The numbers programs actually use

30 days is the most common choice across e-commerce and a reasonable floor. Partners see it as standard; nobody joins or refuses a program over it.

60–90 days is a genuine recruiting advantage for considered purchases, and it costs less than it looks: the marginal sales between day 30 and day 90 are few, but the signal to partners — "we're not trying to stiff you on slow buyers" — helps every recruiting conversation. If you sell memberships or courses, this range fits the buying reality.

Sessions-only or 24 hours shows up in huge marketplace programs that can get away with it. A small program copying that window reads as stingy, and stingy programs pay for it in recruiting — the partners you want can do arithmetic.

365 days mostly signals that nobody thought about it. Very long windows inflate credit for stale recommendations, complicate fraud review, and collide with privacy-driven cookie lifetime limits anyway.

The settings that interact with the window

The window never acts alone. Three neighbors to set deliberately:

• Overwrite behavior. Within the window, does a second affiliate's click replace the first? That's the attribution model question — decide it together with the duration, because a 90-day first-wins cookie and a 90-day last-wins cookie are very different promises.
• Coupon attribution. A personal coupon code credits its owner even when the cookie is long gone — codes survive cleared browsers, mentioned-in-a-podcast moments, and cross-device purchases. A generous code policy quietly patches most cookie-window edge cases.
• Browser reality. Modern browsers cap script-set cookie lifetimes aggressively. First-party, server-involved tracking — the approach described in tracking without third-party cookies — holds a window far more reliably than a JavaScript-only cookie ever will.

Publish it, then leave it alone

Whatever you pick, put the number in your program page and your terms, in plain words: "You earn a commission when a referred visitor purchases within N days of clicking your link." In Affiliate Factory WP the window is one field in the tracking settings, and each referral record shows the originating visit and its date — the demo dashboard shows exactly what a partner-crediting decision looks like from the inside.

Then resist tuning it. Shortening a window reads as a pay cut and will be discussed as one; lengthening it is a cheap goodwill win at annual-review time. A boring, slightly generous number you never touch beats a clever one you keep adjusting.