The Amazon ads attribution window is the number of days after an ad click during which a purchase is counted as an ad sale. For sellers on Sponsored Products it is 7 days; for vendors, and for Sponsored Brands and Sponsored Display, it is 14 days, per Amazon Ads help. The practical effect is that yesterday's ACoS is not final for a week.
When a shopper clicks your ad, Amazon starts a clock. Any purchase of the advertised product (and, for Sponsored Products, other products in your catalogue, reported separately) within the window is attributed to that click and to the campaign, keyword and placement behind it. The sale is dated to the click, not to the purchase. That is why a report for last Tuesday keeps gaining sales until the following Tuesday.
The model is last click. If the shopper clicked two of your ads, the later one gets the sale. Organic visits after the ad click do not reset or break the window. Amazon's help page on attribution is the source for the day counts above; the 7 versus 14 split for sellers versus vendors on Sponsored Products is confirmed in the research notes behind this page.
Spend is recorded the same day. Sales trickle in for a week. A campaign that shows 60% ACoS this morning for yesterday may settle at 35% by next week. Judge campaigns on a period that ended at least 7 days ago.
Raise a bid on Monday and the extra spend shows on Monday; the sales from those clicks arrive through the following Sunday. Do not reverse a change inside the window.
During Great Indian Festival or Prime Day, spend spikes on day one and the attributed sales arrive over the following week. Our post-sale advice is to wait a full window before deciding whether the event paid.
A search term report you pulled on the 5th for the 1st to the 4th is incomplete by definition. Re-pull it a week later before making negative decisions on it.
Sellers mix up three things. The attribution window is the topic of this page. The report lookback is how far back a report can go, and is a separate limit per report type. The new-to-brand window, used in Sponsored Brands metrics, is the 12 months during which a shopper must not have bought from your brand for a purchase to count as new-to-brand. Blooprint's ACoS versus TACoS versus ROAS article covers the metrics themselves; this page is only about the timing.
There is also a difference between sellers and vendors that catches people moving from one to the other. The same Sponsored Products campaign reports more sales under a vendor account simply because the window is twice as long. Do not compare ACoS across the two account types without noting that.
The Amazon console shows one number per date range and leaves you to remember which days are still open. BlooprintAI's analysis views pull data through the Amazon Ads API and mark the trailing window so that provisional days are visible when you filter by ACoS. The filter still runs on the numbers as they stand; the point is that you know which rows might improve on their own before you cut a bid. Every change you then make is reviewed in a summary and logged, and nothing is changed automatically.
Search-term, placement and product-level views that show where the money goes.
Learn more →Ad sales divided by ad spend, with the ACoS equivalent shown alongside.
Learn more →Which of the Amazon Ads reports answers which question, and how often to pull each.
Learn more →The six usual causes of an overnight ACoS jump and how to check each.
Learn more →Seven days for seller accounts and fourteen days for vendor accounts, per Amazon Ads help. A purchase within that window after an ad click is counted as an ad sale and dated to the click.
Both exist. Seven days applies to Sponsored Products for sellers. Fourteen days applies to Sponsored Products for vendors and to Sponsored Brands and Sponsored Display for everyone.
No. Amazon fixes the window by ad type and account type. Amazon Attribution, a separate tool for off-Amazon traffic, uses its own 14-day window.
Sales from clicks in that week kept being attributed for up to seven days after each click. The spend was fixed on the day; the sales caught up, so ACoS fell.
At least one full attribution window after the period you are judging, so seven days after the last day for sellers. For a new campaign that means reading week one no earlier than day 14.
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