A click today might convert next week. The attribution window decides whether you get credit for it.
Main points
- A conversion window is how long after a click a conversion can still be credited.
- Many affiliate programs use last-click attribution: the most recent qualifying click gets the credit.
- Conversions can appear in reports days after the click, especially for considered purchases.
- Browser privacy settings can shorten cookie-based tracking, which is one reason server-to-server tracking is preferred.
When you look at yesterday’s numbers, you’re not seeing the whole picture. Some of yesterday’s clicks will convert tomorrow, or next week.
What a conversion window is
The conversion window, sometimes called the cookie duration, is the period after a click during which a conversion can be credited to you. Common windows range from a single day to a month or more, depending on the offer.
Last-click attribution
Most affiliate programs credit the last qualifying affiliate click before the conversion. If a visitor clicks your link, then later clicks another affiliate’s link and buys, the other affiliate usually gets the commission.
| Situation | Who usually gets credit |
|---|---|
| Click, then convert within the window | You |
| Click, then convert after the window | No one |
| Your click, then another affiliate’s click, then convert | The other affiliate |
| Conversion later reversed | No one |
Why reports change
- Late conversions: considered purchases can take days.
- Reversals: returns, cancellations and failed lead checks remove conversions.
- Tracking gaps: browser privacy features can limit cookie-based tracking.
Pro tip
Judge campaigns on a period longer than the conversion window, such as a full month for a 30-day window, so late conversions are included.
Good practice
Server-to-server postback tracking doesn’t depend on browser cookies, so it’s less affected by privacy settings that limit cookie lifetimes.
Reading reports with the window in mind
Compare offers on similar windows, check reversal rates and give new campaigns time before judging them. Use sub IDs to see where late conversions come from, and keep an eye out for patterns that suggest invalid traffic.
Frequently asked
Can I see an offer’s conversion window?
Usually, in the offer details or terms. If it isn’t listed, ask your affiliate manager.
Why did a conversion disappear?
It may have been reversed after validation, for example a returned purchase, a cancelled trial or a lead that failed quality checks.
Does a longer window always help?
It increases the chance of being credited for slower decisions, but it also means another affiliate’s later click can take the credit under last-click rules.
This article is general information for marketers, not legal advice. Advertising, privacy and consumer protection rules vary by country and change over time, so check the current rules and your network’s terms, and get legal advice where needed before running campaigns.