What is Attribution Window (Meta)?
Also known as: Meta attribution window, Conversion window
What is the Meta attribution window?
A Meta attribution window is the time period after someone clicks or views a Meta ad in which a later conversion will be credited to that ad. If the window is 7-day click, a buyer who clicks today and purchases six days later still counts. Click on day eight, no credit.
The window controls two things at once. It controls which conversions show up in Meta Ads Manager reports. It also controls which conversions Meta's delivery algorithm uses to optimize ad spend. Both settings can be changed independently since 2021 (Meta Business Help Center).
Pick the window wrong and the numbers lie. Pick it right and Meta's reports line up with the real buyer journey.
Available windows after iOS 14
Meta supports four attribution windows in 2026. The 28-day click, 28-day view, and 7-day view options were deprecated in 2021.
| Window | Counts as conversion | Default for | Common use |
|---|---|---|---|
| 1-day click | Click today, convert within 24 hours | Rapid-purchase DTC, food delivery | Conservative reporting, impulse buys |
| 7-day click | Click today, convert within 7 days | New ad sets (default) | Standard ecommerce, most B2C |
| 1-day view | Saw the ad, convert within 24 hours | New ad sets (default) | View-through credit for prospecting |
| 7-day click + 1-day view | Either condition | Combined default | Most ad sets in 2026 |
Three windows are gone. 28-day click, 28-day view, and 7-day view all stopped reporting on new ad accounts after iOS 14.5 rolled out. Meta confirmed the change in its 2021 update on Apple's iOS 14 enforcement (Meta for Developers, Conversions API).
The shorter window means Meta sees less of the funnel than it did in 2020. Reported conversions drop. Reported CPA rises. Same campaign, different math.
Click vs view-through credit
Click attribution and view-through attribution measure different things. Most teams treat them as one number. They should not.
Click credit fires when a buyer clicked the ad and converted later. The intent signal is strong. The buyer interacted on purpose. View-through credit fires when a buyer scrolled past the ad without clicking, then converted within the view window. The intent signal is weak. They might have converted anyway.
Meta's combined default (7-day click plus 1-day view) bundles both. Reported conversions climb 15 to 30 percent versus click-only reporting in most ecommerce accounts. The lift comes from view-through. Strip view-through out and Meta's ROAS often falls below the last-touch attribution numbers in GA4. That's the gap most CFOs catch.
How attribution window choice affects reported ROAS
The window decides which conversions Meta gets to claim. Changing it can swing reported ROAS by 50 percent on the same campaign.
A 30-day test on a $40,000 monthly Meta budget will typically show:
| Window | Reported conversions | Reported ROAS |
|---|---|---|
| 1-day click | 480 | 2.16 |
| 7-day click | 720 | 3.24 |
| 7-day click + 1-day view | 880 | 3.96 |
Same spend. Same campaign. Three different numbers because the window changed. None is wrong. Each measures a different slice of the funnel.
The trap: comparing Meta's 7-day click + 1-day view ROAS against Google's last-click ROAS in GA4 makes Meta look 40 to 60 percent stronger than it actually is on a like-for-like basis. Pick one window and stick with it across channels for budget decisions.
What changed with iOS 14 ATT
Apple's App Tracking Transparency rolled out in iOS 14.5 on April 26, 2021. Users had to opt in to cross-app tracking. Most said no. Meta lost the IDFA signal that powered 28-day attribution windows.
Meta announced four changes in response. The 28-day click window was removed. The 28-day view window was removed. The 7-day view window was removed. The default for new ad sets dropped from 28-day click + 1-day view to 7-day click + 1-day view (Meta Business Help Center, attribution settings).
The Conversions API became the workaround. Server-side events fire from the advertiser's backend, bypass the browser, and survive the ATT prompt. Meta now recommends every advertiser run the Meta Pixel and Conversions API together with shared event_id deduplication (Meta for Developers, Conversions API).
Even with CAPI live, the post-iOS 14 reality is simple. Meta sees less of the funnel than it did. Treat 2026 attribution as directional, not exact.
Real-world example with numbers
A DTC apparel brand spends $60,000 a month on Meta. Average order value: $95. Average funnel length: 4 days from first ad click to purchase.
The team runs the same campaign on three reporting windows for one month. Spend, creative, and audience stay identical.
| Window | Conversions | Revenue | ROAS |
|---|---|---|---|
| 1-day click | 540 | $51,300 | 0.86 |
| 7-day click | 920 | $87,400 | 1.46 |
| 7-day click + 1-day view | 1,140 | $108,300 | 1.81 |
The 1-day click window misses every buyer who researched for two to six days before purchasing. That's 380 real buyers, $36,100 in revenue, hidden by the narrow window.
The 7-day click + 1-day view window adds 220 view-through conversions on top. Some of those buyers would have converted anyway. The team cross-checks against GA4 last-click and finds Meta over-credits by 18 percent on the combined window. They settle on 7-day click as the budget-decision number and use the combined window only for delivery optimization.
That split, narrow window for budget, wide window for optimization, is the 2026 best practice in most performance teams.
Attribution windows in 2026
Three rules hold up across most Meta accounts heading into 2026.
Use 7-day click as the reporting default. It captures the real funnel for any AOV above $50 without leaning on view-through. Use the combined 7-day click + 1-day view window for delivery optimization. Meta's algorithm needs view-through signal to find prospecting audiences. Use one consistent window across all channels in your blended ROAS dashboard. Mixing Meta's 7-day click + 1-day view against Google's last-click distorts every budget call.
The deeper shift is structural. Meta's window settings exist because the platform owns the report. A third-party multi-touch attribution tool or a first-touch attribution view will always tell a different story than Ads Manager. That's not a bug. It's the point of cross-channel measurement.
The window is a lens, not a verdict. Read three lenses every quarter and the truth shows up in the overlap.
Related terms
Frequently asked questions
What is the default attribution window in Meta Ads Manager in 2026?
The default is 7-day click and 1-day view. Meta sets it on every new ad set and uses it for ad delivery optimization. You can change the reporting window without changing the optimization window. The two settings are separate inside Ads Manager (Meta Business Help Center).
Why was the 28-day attribution window removed?
Apple's iOS 14.5 App Tracking Transparency rule blocked the IDFA signal Meta used to track users across apps and websites for 28 days. Meta announced the change in 2021 and dropped 28-day click, 28-day view, and 7-day view as supported windows (Meta for Developers).
What is the difference between click and view-through attribution?
Click attribution credits a conversion when the buyer clicked the ad before converting. View-through credits a conversion when the buyer only saw the ad and converted later without clicking. View-through inflates Meta's reported numbers, so most analysts compare click-only ROAS in third-party tools.
How does the attribution window affect reported ROAS?
Wider windows attribute more conversions, so reported ROAS climbs. A campaign showing 2.4 ROAS on 1-day click often shows 3.6 on 7-day click because mid-funnel buyers take days to return. Narrow windows underreport. Wide windows over-credit Meta versus other channels in multi-touch attribution reports.
Should I use a 1-day or 7-day click attribution window?
7-day click is the right default for most accounts. 1-day click suits rapid-purchase categories like food delivery or impulse DTC under $30 AOV. Anything with a research phase, comparison shopping, or AOV above $80 needs the 7-day window to capture the real funnel.