Affiliate cookie windows explained (and how to set yours)

The cookie window is one of the most consequential — and least understood — settings in an affiliate program. It quietly decides who gets paid for a sale. Set it wrong and you either underpay your partners or overpay for sales they didn't really cause. Here's how it works, and how to choose yours.

What is an affiliate cookie window?

A cookie window (or attribution window) is the stretch of time after someone clicks an affiliate's link during which a resulting purchase still credits that affiliate. Set a 30-day window, a buyer clicks today and buys three weeks later, and the affiliate earns the commission. Once the window expires, the click no longer counts.

How does the cookie window affect attribution?

Window length changes who earns credit and how much you pay. A longer window credits affiliates for buyers who take time to decide — partners love that — but it can also pay for sales other channels really closed. A shorter window ties credit tightly to fresh intent, but may under-reward affiliates who genuinely planted the seed.

• Longer window (60–90 days): generous to affiliates, good for considered purchases, but risks over-attribution.
• Shorter window (1–7 days): conservative, best for impulse buys, but risks under-rewarding real influence.
• Medium window (30 days): the common default, balancing both for most businesses.

How long should your cookie window be?

Match the window to how long your buyers actually take to decide. Measure the typical gap between first touch and purchase, then set the window to cover it comfortably — without stretching so far you pay for influence that wasn't really yours.

1. Impulse or low-price products: a few days is plenty.
2. Mid-consideration consumer purchases: 30 days is the sensible default.
3. Considered B2B or high-ticket SaaS: 45–90 days matches the longer evaluation.

What about last-click vs. other attribution models?

Most affiliate programs use last-click within the cookie window — the last affiliate clicked before purchase gets the credit. It's simple and widely understood, but you can also weigh first-click (rewarding discovery) or splitting credit. Whatever you pick, state it in your terms so partners know exactly how they're credited.

What does cookieless tracking mean for the future?

Third-party cookies are increasingly blocked or short-lived, so attribution is moving to server-side and first-party methods. Modern platforms record clicks server-side and tie conversions to first-party identifiers instead of leaning on a browser cookie, which keeps attribution accurate even as browsers tighten privacy. When you evaluate tracking, ask how it copes in a cookieless world.

The cookie window isn't a technical detail — it's a promise to your partners about how fairly you'll credit the demand they create.