Definition
A cookie window, also called an attribution window or lookback window, is the number of days a tracking cookie remains active after a visitor clicks an affiliate link. If the visitor converts within that window, the affiliate gets credit. If the cookie expires before the conversion, the affiliate earns nothing for that referral. Most programs set cookie windows between 30 and 90 days.
The cookie window is one of the most important settings in your affiliate program because it directly determines how much credit your partners receive and how attractive your program is to prospective affiliates.
How a cookie window works
A visitor clicks an affiliate's link on March 1st. Your tracking system drops a first-party cookie on that visitor's browser with an expiration date based on your cookie window. If you have set a 30-day window, the cookie expires on March 31st. If the visitor comes back on March 20th and buys, the cookie is still valid, the system reads the affiliate ID from it, and the affiliate is credited. If the visitor waits until April 5th, the cookie has expired and the conversion is unattributed.
Some programs use different windows for different actions. You might set a 90-day window for first-time purchases but a 7-day window for upsells. The right duration depends on your typical sales cycle. A $10 impulse buy does not need 90 days. A $10,000 enterprise deal might need longer.
Common cookie window durations
The right window length varies by industry and product type, but common benchmarks provide a starting point.
7 days is typical for impulse purchases, low-cost products, and offers where the customer either buys immediately or not at all. Mobile apps, free trials, and low-ticket ecommerce often use 7-day windows.
30 days is the most common default across affiliate programs. It covers the typical consideration period for mid-range products and services. Amazon's affiliate program famously uses a 24-hour window (with a 90-day extension if the item is added to cart), which is unusually short but works because of Amazon's high conversion rates.
60-90 days is appropriate for higher-consideration purchases like software subscriptions, financial products, and B2B services where the sales cycle is longer. Affiliates promoting these products invest more time in education and content, so a longer window is fair compensation for that effort.
Lifetime or session-based windows are rare but exist. Some programs credit the affiliate for any conversion from a referred customer, regardless of when it happens. This is most common in referral programs (as opposed to traditional affiliate programs) and subscription businesses that want to reward the initial referrer for the entire customer lifetime.
How browser restrictions affect cookie windows
Even if you set a 90-day cookie window, the browser might not honor it.
Safari's Intelligent Tracking Prevention (ITP) limits third-party cookies to 24 hours and caps some first-party cookies set via JavaScript to 7 days. Firefox's Enhanced Tracking Protection applies similar restrictions. Chrome has introduced comparable measures.
This means your configured cookie window is only a maximum. The actual window depends on the type of cookie, how it is set, and which browser the visitor uses. A 90-day window with a third-party cookie on Safari effectively becomes a 24-hour window.
The solution is first-party tracking via a CNAME setup on your domain. First-party cookies set server-side via HTTP headers respect the full window duration you configure. For maximum reliability, pair cookie-based attribution with server-to-server tracking that is not affected by browser restrictions at all.
Why your cookie window matters
Your cookie window directly affects affiliate recruitment and retention. Longer windows are more attractive to affiliates because they protect the affiliate's investment in driving awareness even if the customer takes weeks to decide. Shorter windows reduce your risk of paying for conversions that were influenced by other channels after the initial click.
The tension is real. Set it too short and affiliates feel cheated when their referrals convert a day after expiry. Set it too long and you might be crediting affiliates for organic customers who would have converted anyway.
The right approach is to look at your data. Pull your average time from first visit to purchase and add a reasonable buffer. If your median time to conversion is 12 days, a 30-day window gives plenty of headroom. If it is 45 days, you need at least 60 days.
Cookie window length is also a competitive lever. If competing programs in your niche offer 30-day windows and you offer 90 days, affiliates are more likely to promote your program because their referrals are protected longer. Conversely, if you offer 7 days while competitors offer 30, you will struggle to recruit experienced affiliates.
Frequently asked questions
What is a good cookie window for affiliate programs?
30 days is the most common default and works well for most programs. If your product has a longer consideration period (B2B, financial services, high-ticket items), extend to 60-90 days. If conversions typically happen within hours (mobile apps, impulse buys), 7-14 days is sufficient. Check your conversion data to see how long referrals typically take to convert, and set the window to cover at least 90% of those conversions.
What happens when a cookie window expires?
When the cookie expires, the tracking link between the original click and any future conversion is broken. If the visitor comes back and converts after expiry, the conversion is recorded but attributed to no affiliate. The partner who originally drove the traffic receives no commission. Some programs supplement cookies with server-side tracking to maintain attribution beyond cookie expiry.
Can different affiliates have different cookie windows?
Yes, many programs offer longer cookie windows to high-performing partners as an incentive. A standard affiliate might get a 30-day window while a top-tier partner gets 90 days. This rewards investment and gives your best partners extra protection. Your tracking platform needs to support per-partner window configuration for this to work.
What is the difference between a cookie window and a conversion window?
They are often used interchangeably, but there is a subtle distinction. A cookie window refers specifically to how long the tracking cookie persists in the browser. A conversion window is the broader concept of how long after a click a conversion can be attributed, which might include server-side methods that do not depend on cookies. In practice, most people use both terms to mean the same thing.
Trcker tip
Trcker lets you configure different cookie windows per program and per partner tier, giving you the flexibility to reward high-value affiliates with longer attribution periods. Combined with first-party cookies and server-to-server postbacks, your configured window is the actual window, not a theoretical maximum that browsers override.