The attribution window on Amazon Ads is the period after a shopper clicks (or, for some ads, views) your ad during which Amazon will still credit a purchase to that ad. Sponsored Products has traditionally used a 7-day window and Sponsored Brands a 14-day one, and since 1 January 2026 Amazon has also changed how it credits ad views on Store placements. If you read ACoS, ROAS or ad sales without knowing which window sits behind them, you can easily misjudge a campaign.
This guide explains the windows, what changed, why your numbers shift from day to day, and how to turn all of it into better bidding and profit decisions.
TL;DR
- An attribution window is the time Amazon allows between an ad interaction and a purchase for that sale to count as ad-attributed.
- Click-based attribution did not change in 2026. What changed is view-based credit for Sponsored Brands, vCPM Sponsored Display and Amazon DSP ads served in the Store.
- Recent days in your reports are incomplete, because sales from clicks can still arrive for days afterwards. Do not cut bids on a campaign because yesterday looks weak.
- Attributed sales are not the same as profit. Compare ad results with your margin and total sales, not with ACoS alone.
- Always check which window a column uses (1-day, 7-day, 14-day, 30-day) before comparing two campaigns or two tools.
Table of Contents
- What the attribution window means
- Windows by campaign type
- What changed on 1 January 2026
- Click-through versus view-through attribution
- Why recent sales keep changing in your reports
- How to read attribution-window metrics
- From attributed sales to profit
- Our perspective
- Putting this into your workflow with Osellpa
- A simple routine for reading windows well
- FAQ
- Sources
What the attribution window means
When a shopper interacts with your ad and later buys, Amazon needs a rule for deciding whether the ad earned that sale. The attribution window is that rule’s time limit. If the purchase falls inside the window, the sale is attributed to the ad. If it falls outside, the sale still happens, but it shows up as organic or unattributed.
Two ideas sit inside every window:
- The trigger. Usually a click. For some Store ad formats, an ad view can also be a trigger.
- The credit rule. Amazon uses a last-touch approach: the most recent qualifying interaction receives the credit. Amazon’s guide to Amazon Attribution describes a 14-day, last-touch model for that tool: a conversion must happen within 14 days of a click, and the most recent click gets the credit.
That matters because the window is not a measure of how good your ad is. It is a measuring stick. A longer window will always show more attributed sales than a shorter one for the same shoppers, and a shorter window will show a lower number without anything having gone wrong.
Windows by campaign type
The most useful starting point is the standard windows sellers work with. Amazon’s Seller Central guidance, now several years old, gives the standard window as 7 days for Sponsored Products and 14 days for Sponsored Brands, and notes that Sponsored Products reports can show windows from 1 to 30 days. Because Amazon revises its reporting, confirm the current setup in your own console before you rely on any figure.
| Ad type or tool | Window traditionally used | What to remember |
|---|---|---|
| Sponsored Products | 7 days | Reports can also expose other windows, so check column headings |
| Sponsored Brands | 14 days | Affected by the 2026 view-attribution update for Store placements |
| Sponsored Display (vCPM) | See Amazon’s update | View-based credit changed from 1 January 2026 |
| Amazon DSP in the Store | See Amazon’s update | View-based credit changed from 1 January 2026 |
| Amazon Attribution (off-Amazon traffic) | 14 days, last touch | Clicks from external channels such as email or social |
For the exact current behaviour of each type, use Amazon’s own pages, and for our fuller walk-through see our article on what 7- and 14-day windows mean for sellers.
Amazon Attribution is a separate tool
Amazon Attribution measures traffic you send to Amazon from outside it: search ads, social posts, email, influencers. According to Amazon’s product page, its reports cover clicks, detail-page views, add-to-cart, purchases, units sold, product sales and new-to-brand metrics over a 14-day attribution window. If you run external traffic, our guide to scaling Amazon Attribution tags shows how to set it up at volume.
What changed on 1 January 2026
The change that prompted many searches for this topic is Amazon’s view attribution update for Store ads. In plain terms:
- Amazon introduced a shopping-signal-enhanced last-touch model for eligible ad views in the Store. It gives credit to views that reach shoppers at early discovery moments, and applies a shorter attribution window.
- It affects Sponsored Brands, Sponsored Display campaigns billed on a vCPM basis (including branded-keyword campaigns) and Amazon DSP campaigns serving ads in the Store.
- Conversion reporting for other campaign and inventory types stays unchanged, and click-based attribution stays unchanged.
- You can still see conversion metrics covering all ad views within 14 days. They appear as “all views” metrics, such as Purchases (all views), in Unified Reporting interfaces and APIs.
What this means in practice
If you run Sponsored Brands or vCPM Sponsored Display, expect purchases, sales and ROAS for the new methodology to be the standard figures, and expect them to look lower than before for view-driven sales. That drop is a change in measurement, not necessarily in shopper behaviour. Your Sponsored Products click-based results should be broadly comparable with last year.
A sensible approach:
- Note the date you first saw the change in your account.
- Mark that date on any performance chart you keep.
- When you compare 2026 with 2025 for affected ad types, use the “all views” metrics for a like-for-like view.
- Judge new bids and budgets on the standard metrics from now on.
Click-through versus view-through attribution
A click-through sale happens when a shopper clicks the ad and buys within the window. It is the cleaner signal: the shopper took an action, and you paid for it (on cost-per-click formats).
A view-through sale happens when a shopper sees the ad without clicking and later buys. It is harder to prove that the ad influenced the purchase, which is exactly why Amazon narrowed how view credit works in 2026.
For most UK sellers, the practical rule is simple: make decisions on click-based sales first, and treat view-based figures as supporting evidence of awareness. If a Sponsored Brands campaign shows strong view-based sales but weak click-based sales, the question to ask is whether it is building demand or just sitting in front of shoppers who would have bought anyway. Our guide to Sponsored Brands video and to Sponsored Display audiences go deeper on testing each format.
Why recent sales keep changing in your reports
Because the window runs forward from the click, a click today can still produce an attributed sale later. Amazon’s Seller Central example makes this concrete: a Sponsored Products click on 29 January followed by a purchase on 3 February is included because the purchase happened five days after the click.
Two effects follow:
- The latest days look worse than they are. Spend is recorded straight away, but sales trickle in over the window. ACoS for yesterday will usually fall as those sales arrive.
- Month boundaries can mislead. Amazon’s guidance warns that a month-to-date range may leave out later-attributed sales from clicks made in the previous month, while a last-month range can include them. Reading the first week of a month against the closing figures of the last one will make the new month look weaker.
A worked example
Imagine a Sponsored Products campaign that spends £50 over Monday and Tuesday. On Wednesday morning the report shows £60 of attributed sales, an ACoS of about 83%. By the following Monday, as more purchases from those clicks land inside the 7-day window, the same two days might show £180 of sales and an ACoS of about 28%. Nothing about the ads changed. Only the data matured.
The figures above are an illustration of the mechanics, not a benchmark. The point is the habit: before you pause a keyword or cut a bid, look at days old enough to have completed their window.
How to read attribution-window metrics
Amazon’s UK guidance defines the main figures in a way worth keeping in mind. Attributed sales are the value of products sold within the campaign timeframe because of clicks on ads. Orders are Amazon orders submitted after shoppers clicked, and spend is the total click charges for the campaign.
A few reading habits help:
- Check the column label. Metrics such as 1-day ACOS use a different sales figure from 7-day or 14-day versions. Amazon’s metrics glossary spells out that the 1-day figure divides total ad cost by 1-day total sales. Comparing a 1-day column with a 7-day column is comparing different things.
- Keep windows consistent. If you export reports to a spreadsheet or another tool, use the same window for every campaign you compare.
- Separate brand halo. Amazon’s Attribution guide defines brand halo as conversions on products from the same brand as the promoted ones, excluding the promoted products themselves. A campaign can look unprofitable on its own product and still lift sister products.
- Treat new-to-brand as a different question. Amazon defines new-to-brand purchases as first-time purchases of promoted products within the brand over a one-year lookback. That is a customer-acquisition metric, not a window setting. See our guide to tracking new customer cost in new-to-brand ads.
From attributed sales to profit
Even a perfectly understood window only tells you which sales the ads claimed. It does not tell you whether you made money. Three checks close that gap.
1. Compare ACoS with break-even
Your break-even ACoS is your contribution margin after Amazon fees and product costs, before advertising. Any campaign running above it loses money on the attributed sale, though it may still earn back through repeat orders or halo. Our piece on break-even ACoS and wasted spend for UK sellers shows how to set it.
2. Look at total sales, not only ad sales
A campaign can show excellent ACoS because it captures sales that would have come organically. TACoS (total advertising cost divided by total sales) shows whether your advertising is growing the whole business. We explain the approach in using 90-day TACoS, and a 90-day view naturally smooths out the lag the attribution window creates.
3. Remove waste before adjusting windows
You cannot change the standard window for most campaign types, but you can control what your ads spend on. Adding negative keywords and targets usually does more for results than debating window length. Start with negatives first.
Our perspective
We see the same mistake from sellers of every size: they treat the report as final the moment it loads. Windows make that impossible. A report is a moving picture for the last week or two, and the cleanest decisions come from data that has finished maturing.
The 2026 change reinforces a second point. When Amazon alters how credit is assigned, your historical benchmark can shift without your campaigns changing. That is why we build Osellpa around keeping a clear profit view next to the ad view. Ad metrics answer “what did Amazon credit?”, while profit tracking answers “what did I keep?”. You need both, side by side, with the window noted.
Our practical advice for anyone running more than a handful of campaigns:
- Set a fixed review rhythm, for example weekly decisions on data at least a week old.
- Judge Sponsored Products on click-based results and treat view-based figures as context.
- Keep a note of the date measurement rules changed, so you do not blame a bid change for a reporting change.
- Tie every ad decision back to margin after fees, returns and costs, not to ACoS in isolation.
— Harry
Putting this into your workflow with Osellpa
Osellpa connects to Amazon through its API and brings profit tracking, PPC optimisation and alerts into one place, so you are not stitching together spreadsheets to check whether a campaign pays once fees are counted. Our profit and loss software shows your real margin per product, and the seller dashboard puts ad performance beside it.
Plans on our pricing page are Launch at £10 per month (£96 per year), Scale at £20 per month (£192 per year) and Advanced at £40 per month (£384 per year). Plans are based on your Amazon sales volume, so check the page to see which tier fits you.
A simple routine for reading windows well
- Pick the window per ad type and write it down. Use the same one for every comparison.
- Exclude the newest days from any decision about pausing or cutting bids.
- Use full calendar ranges when comparing months, so late-attributed sales are included.
- Mark measurement changes, such as the 1 January 2026 Store update, on your charts.
- Check profit, not just ACoS, with break-even and TACoS next to each campaign.
- Review brand halo and new-to-brand before shutting down a campaign that looks weak on its own product.
FAQ
What is the attribution window in Amazon Ads?
It is the period after a shopper interacts with your ad during which a purchase is credited to that ad. Amazon uses a last-touch approach, so the most recent qualifying interaction gets the credit. The length depends on the campaign type and the report you are reading.
How long is the attribution window for Sponsored Products?
Amazon’s Seller Central guidance has described a standard 7-day window for Sponsored Products, with reports able to show other windows from 1 to 30 days. Check the column label in your report, as reporting options change over time. Click-based attribution was not changed in the 2026 Store update.
Did Amazon change attribution in 2026?
Yes, for view-based credit. From 1 January 2026, Amazon applied a shopping-signal-enhanced last-touch model and a shorter window to Sponsored Brands, vCPM Sponsored Display and Amazon DSP ads in the Store. Other campaign and inventory types, and click-based attribution, stayed unchanged, and “all views” metrics remain available over 14 days.
Why do my sales for the last few days keep rising?
Because purchases can still be attributed to clicks that happened days earlier. Spend appears immediately, while sales arrive across the window. Wait until the window has passed before judging ACoS for a given day.
Can I change the attribution window?
For most standard campaigns you cannot choose the window, but you can choose which reported window you read. Pick one consistently, and use Amazon’s own documentation to confirm what each metric covers.
Sources
- Your complete guide to Amazon Attribution | Amazon Ads
- View Attribution Updates for Amazon Store ads | Amazon Ads
- Amazon Attribution: Get started with advertising analytics | Amazon Ads
- What are the 7-day columns in the advertising reports? | Amazon Seller Central
- Advertising your brand on Amazon | Amazon Ads
