By Kristians, Founder, AutoAdy. Six years buying Meta ads — first for agency clients, then for his own ecommerce and lead-gen brands.
Last updated:
What changed: Added an attribution-window table, linked Meta's API documentation, and added the free ROAS calculator.
Meta's default attribution window is 7-day click and 1-day view, meaning it claims credit for conversions up to 7 days after a click or 1 day after a view. This default over-reports conversions by 15-30% compared to last-click models. Understanding attribution is critical for accurate ROAS measurement.
Key Takeaways
Attribution determines which ad gets credit for a conversion. Meta's 7-day click window: someone clicks Monday, buys Friday — ad gets credit. The 1-day view window: someone sees (doesn't click) your ad and converts within 24 hours — Meta still claims it. This is generous — 15-30% of reported conversions wouldn't appear under last-click models. Use 1-day click for conservative numbers closer to Google Analytics.
Pick the window that matches the question you are asking. Post-iOS 14.5 Meta also adds modeled conversions to fill pixel gaps, which puts another 10-15% on top of whichever window you choose.
| Window | What it counts | When to use it |
|---|---|---|
| 7-day click / 1-day view | Clicks within 7 days plus views within 24 hours | Meta's default — full path, with 15-30% inflation baked in |
| 7-day click only | Clicks within 7 days, no view-through | When you suspect view-through is over-counting |
| 1-day click only | Clicks converting the same day | Most conservative — compare against Google on equal footing |
AutoAdy shows performance across multiple attribution windows simultaneously. It flags campaigns where view-through exceeds 40% of conversions — a sign reported ROAS may be inflated.
Figures below come from Meta ad accounts AutoAdy has audited or monitors. They are directional, not a controlled study.
FAQ
Meta uses 7-day click attribution (vs Google's last-click) and counts view-through conversions. Together these inflate Meta's numbers 15-30%. Use 1-day click for apples-to-apples comparison.
Don't turn it off entirely — it captures real awareness value. Run reports with and without view-through to understand the gap. If view-through exceeds 40% of conversions, true ROAS is 20-30% lower than reported.
After iOS 14.5, Meta can't track all conversions via pixel. It estimates missed conversions statistically, adding ~10-15% to reported numbers. Directionally accurate but not exact — cross-reference with CRM data.
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