Attribution Windows Guide 2026: Meta vs Google & Best Practices

Key Takeaways

• Meta's default is 7-day click, 1-day view (restricted from pre-iOS 14 28-day windows)
• Google allows 1-90 day attribution windows with various models
• Meta is removing 7-day and 28-day view-through windows in January 2026
• Incremental Attribution from Meta shows 20%+ boost in incremental conversions
• Window misalignment guarantees reporting disagreement between platforms

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Understanding Attribution Windows

Attribution windows define how long after an ad interaction a conversion can be credited to that ad. Get this wrong, and you'll make decisions based on inaccurate data.

The Basic Concept

User sees ad → [Window opens] → User converts → [Credit assigned?]
      ↑                                              ↑
  Impression/Click                        Only if within window

Window Types

Type	Definition	Best For

Click-through	Conversion after clicking	Direct response
View-through	Conversion after seeing (no click)	Awareness, brand
Engaged-view	Video watch of 10+ seconds	Video campaigns

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Meta Attribution Windows

Available Options (2026)

Window	Description	Use Case

1-day click	24 hours after click	Impulse purchases
7-day click	7 days after click	Most e-commerce
1-day view	24 hours after impression	Brand influence
7-day click + 1-day view	Default setting	Balanced approach

The iOS 14 Impact

> "Before Apple's iOS 14.5 update, Meta offered advertisers detailed attribution insights, with windows extending up to 28 days post-click and 7 days post-view."

What Changed:

• 28-day click window removed
• 7-day view window being removed (Jan 2026)
• More limited data granularity
• Modeled conversions for iOS users

Incremental Attribution (2025)

> "In April 2025, Meta rolled out Incremental Attribution, an AI-powered technique that uses holdout testing to separate conversions driven by ads from those that occur naturally."

Benefits:

• 20%+ boost in incremental conversions identified
• True incrementality measurement
• AI-powered holdout testing
• Better budget allocation insights

Choosing Meta Windows

Scenario	Recommended Window

Impulse products (<$50)	1-day click
Standard e-commerce	7-day click
High-consideration ($500+)	7-day click
Brand awareness	7-day click + 1-day view
Flash sales	1-day click

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Google Ads Attribution

Window Options

Platform	Min Window	Max Window	Default

Google Ads (Search)	1 day	90 days	30 days
Google Ads (Display)	1 day	90 days	30 days
Google Ads (Video)	1 day	90 days	30 days
GA4	1 day	90 days	30 days

Attribution Models in Google

Model	Description	Best For

Data-Driven	ML-based credit distribution	Most advertisers
Last Click	100% to final click	Direct response
First Click	100% to first click	Awareness campaigns
Linear	Equal credit to all	Understanding full path
Time Decay	More credit to recent	Shorter cycles
Position-Based	40/20/40 first/middle/last	Balanced view

Google's Time Decay

> "Google differs from Meta in that credit is distributed through a 7-day half life. An ad interaction 8 days before the conversion event gets half as much credit as an interaction 1 day before."

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Platform Comparison

Key Differences

Factor	Meta	Google

Max click window	7 days	90 days
View-through	1 day (soon limited)	Varies by campaign
Default model	Last touch	Data-driven
Cross-device	Limited post-iOS 14	Better with login data
Granularity	Restricted	More detailed

Why Numbers Never Match

> "Window misalignment guarantees numerical disagreement."

Causes of Discrepancy:

Different attribution windows

Different attribution models

Different conversion definitions

Cross-device tracking differences

View-through methodology

Time zone differences

Conversion delay handling

Comparing Apples to Apples

To minimize discrepancy:

• Align windows where possible
• Use same conversion events
• Understand each platform's methodology
• Don't expect 100% match
• Use incrementality testing for truth

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Setting Up Attribution

Meta Attribution Settings

Location: Ads Manager → Ad Set Level → Attribution Setting

Setting	Options

Click window	1-day or 7-day
View window	1-day or none
Combination	Click-only or Click + View

Google Ads Attribution Settings

Location: Tools & Settings → Measurement → Attribution

Setting	Options

Model	Data-driven, Last click, etc.
Window	1-90 days
Conversions	Include in conversions toggle

GA4 Attribution Settings

Location: Admin → Attribution Settings

Setting	Options

Reporting model	Data-driven or rules-based
Lookback window	Acquisition: 30 days default
Other: 90 days default

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Attribution Strategy by Business Type

E-commerce

Factor	Recommended Approach

Meta	7-day click for most products
Google	30-day click for standard, 7-14 for impulse
High AOV	Longer windows (consider full journey)
Low AOV	Shorter windows (impulse behavior)

Lead Generation

Factor	Recommended Approach

Meta	7-day click (form fills are quick decisions)
Google	30-60 day for B2B, 14-30 for B2C
Long sales cycle	Supplement with offline conversion import
Short sales cycle	7-14 day windows

Subscription/SaaS

Factor	Recommended Approach

Trial signups	7-30 day click
Paid conversions	30-60 day
Enterprise	60-90 day, plus CRM integration
Consumer	14-30 day

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View-Through Attribution

The Debate

View-through attribution credits conversions to users who saw but didn't click your ad. It's controversial:

Arguments For:

• Captures awareness influence
• Recognizes brand impact
• More complete picture
• Especially relevant for video/display

Arguments Against:

• Hard to prove causality
• Inflates reported performance
• Can overlap with other channels
• Open to manipulation

Best Practices

Use conservatively — 1-day view maximum

Compare with and without — Understand the delta

Consider incrementality — View-through lift testing

Don't double count — Deduplicate across channels

Question high view-through — If most conversions are VT, investigate

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Advanced Attribution Approaches

Incrementality Testing

The gold standard for true attribution:

Holdout groups — Don't show ads to control

Geo testing — Dark markets vs. exposed

Conversion lift — Platform-native measurement

Matched market analysis — Statistical comparison

Marketing Mix Modeling (MMM)

For macro-level attribution:

• All channels together
• Historical data analysis
• Accounts for external factors
• No individual tracking needed
• Privacy-compliant

Multi-Touch Attribution (MTA)

Distributes credit across touchpoints:

• Requires cross-channel data
• Various models available
• Better than last-touch alone
• Still limited by tracking gaps

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Common Mistakes

1. Using Misaligned Windows

Comparing Meta 7-day to Google 30-day makes no sense. Align or understand the delta.

2. Ignoring Window in Optimization

Meta optimizes for your chosen window. Wrong window = wrong optimization.

3. Over-Relying on View-Through

High view-through conversion percentages should trigger skepticism, not celebration.

4. Forgetting Conversion Delay

Some conversions take days/weeks. Don't evaluate campaigns before window closes.

5. Not Testing Windows

Your optimal window may differ from defaults. Test different settings.

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The Bottom Line

Attribution windows in 2026 require:

Platform understanding — Meta and Google work differently

Business alignment — Match windows to purchase cycle

Consistency — Same settings across similar campaigns

Skepticism — Question high view-through rates

Supplemental testing — Incrementality for truth

Adaptability — Privacy changes will continue

> "The right approach is to use multiple measurement methods by combining attribution, MMM, and incrementality testing for a complete picture."

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AdBid normalizes attribution across platforms, showing you comparable data regardless of window settings. Understand your true performance. See unified attribution.