Why is GA4 not matching my ad platform conversions?

Most GA4 vs ad platform conversion gaps come from different attribution models, lookback windows, counting methods, and data loss (ad blockers, consent). Also check time zones, currency, tag firing, cross-domain setup, and conversion lag. Align definitions and windows, verify tagging, and reconcile using the same attribution view before escalating to a data-quality fix.

Common causes of mismatches

Attribution differences (data-driven vs last-click), lookback windows (90 vs 7 days), and counting rules (one-per vs every) are the top drivers. Add technical factors: consent mode and ad blockers reduce GA4 signals, cross-domain or SPA routing can drop session linkage, and missing transaction values skew ROAS. Time zone and currency mismatches further misalign day-level comparisons.

How to reconcile step-by-step

Start with a fixed date range after conversion lag (e.g., last full 14 or 28 days). In GA4’s Advertising workspace, use Model comparison to mirror the ad platform’s model and window. Standardize time zone/currency. Validate tags with DebugView and Tag Assistant; check transaction_id, value, and enhanced conversions. Ensure gclid/fbclid persist and cross-domain is configured. Document residual variance.

When to change implementation vs expectations

If gaps stem from modeling or privacy (iOS, consent), expect persistent deltas and align expectations by comparing at weekly cadence and consistent models. If gaps come from tagging (missing value, duplicate purchases, broken cross-domain), fix implementation first. For media optimization, choose a single conversion source in each platform and keep definitions consistent across channels.

Why do my platform ROAS and GA4 revenue not align?

Platforms often use last-click (or network-favored) attribution with shorter windows, while GA4 defaults to data-driven with cross-channel credit. GA4 also excludes taxes/shipping by default and respects consent/ad blockers. Align attribution model and lookback windows, confirm currency/time zone, and ensure purchase value parity in tags. Compare using the same model in GA4’s Advertising section to reconcile.

How can I reconcile Google Ads conversions with GA4 accurately?

Pick one source of truth per use case. For media optimization, import GA4 conversions into Google Ads or use the native Google Ads tag consistently. Align conversion actions, attribution model, and lookback windows. Confirm auto-tagging (gclid), cross-domain, and enhanced conversions. Then compare GA4 Advertising > Model comparison to match the Ads setting before finalizing.

What settings cause the biggest GA4 vs Meta (Facebook) conversion gaps?

Common drivers: mismatched attribution windows (e.g., 7-day click vs GA4 default), modeled conversions in Meta, iOS ATT signal loss, blocked fbclid, and consent mode in GA4. Standardize lookback windows, use CAPI/enhanced conversions where possible, verify UTMs and landing page param preservation, and compare on the same time zone and day-of-conversion definition.

How long should I wait before comparing conversions across platforms?

Allow for conversion lag and late attribution. E-commerce typically stabilizes in 3–7 days; B2B or subscription flows may need 14–28 days. Some platforms backfill modeled conversions. Lock the comparison window after lag (e.g., last full 7 or 28 days), then reconcile using identical attribution windows and models to avoid moving targets.

Could tagging issues cause GA4 undercounting?

Yes. Misplaced tags, double SPA navigations, broken consent integration, missing purchase value, or cross-domain gaps can drop conversions. Validate with GA4 DebugView and Tag Assistant, confirm event parameters (value, currency, transaction_id), ensure one purchase event per order, preserve URL params (gclid/fbclid), and implement server-side/enhanced conversions where needed.

How do time zone and currency differences skew conversion comparisons?

If GA4 and ad platforms use different time zones, conversions and revenue fall into different days, skewing daily comparisons. Currency mismatches inflate or deflate revenue and ROAS. Standardize to the same time zone and currency across GA4 and platforms. When that’s not possible, compare on weekly ranges and convert currency consistently before analysis.

What’s the fastest checklist to diagnose GA4 vs platform discrepancies?

1) Align attribution model/window. 2) Match time zone/currency. 3) Validate tags and consent; check purchase value/transaction_id. 4) Confirm cross-domain and param preservation. 5) Account for conversion lag. 6) Remove double-counting or duplicates. 7) Compare in GA4’s Advertising workspace using the same model as the ad platform. Document residual gaps.

See also

Explore features to get weekly variance analysis and anomaly alerts, or view Integrations to connect GA4, Google Ads, Meta, and Search Console for consistent reconciliation.