> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.omegatheme.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# 🗓️ Facebook Attribution

Meta's attribution model has changed a lot since 2021. Here's what it looks like in 2026 — and where to dig deeper.

### What Meta attribution windows look like now
| **Window** | **What it credits** | **Default** |
| **1-day view** | Conversion within 24h of seeing your ad (no click) | Yes |
| **1-day click** | Conversion within 24h of clicking your ad | Optional |
| **7-day click** | Conversion within 7 days of clicking | ✅ Yes |
| **28-day click** | Conversion within 28 days of clicking | Optional |
| 1-day engage-through (new Mar 2026) | Conversion within 24h of liking or saving your ad | ✅ Yes |

|| ⚠️ Removed Jan 12, 2026: 7-day view and 28-day view. If your reported conversions dropped 10–25% overnight in early 2026, this is why.

### Three things every advertiser should understand

1. **Reporting can lag up to 72h.** Meta backfills late-attributed conversions over multiple days. Don't optimize on yesterday's numbers — see [⏳ Fix your Facebook reporting delay.](https://help.omegatheme.com/en/article/fix-your-facebook-reporting-delay-tn2qde/?bust=1780449514576)
2. **Some data is just lost.** iOS opt-outs, ad blockers, cookie limits — these conversions can't be attributed even when they happen. See [🔍 Understanding data absence.](https://help.omegatheme.com/en/article/understanding-data-absence-1whdgbi/?bust=1780449514574)
3. **iOS 14 wasn't the only blow.** Meta has reshaped attribution multiple times since — 2024 (DPA → Advantage+), Jan 2026 (window removal), March 2026 (engage-through). See [📦 How Meta attribution changed.](https://help.omegatheme.com/en/article/how-meta-attribution-changed-20212026-m2fcjq/?bust=1780451041718)