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Google tag (gtag.js) vs Google Tag Manager: which slows a Shopify store more?

Google Tag Manager is usually the lighter of the two. On the typical store it was moderate, while Google tag (gtag.js) was heavy.

Both are tag managers. We measured Google tag (gtag.js) on 546 Shopify ecommerce stores and Google Tag Manager on 430.

Tag manager

Side by side

AppTypical processing timeStores measured
Google tag (gtag.js) Heavy (300 ms to 1 second) 546
Google Tag Manager Moderate (100 to 300 ms) 430

Google tag (gtag.js) was heavy on 75% of the stores it was measured on. Google Tag Manager was moderate on 42% of the stores it was measured on.

On stores that run both

408 of the stores we checked load both. Google Tag Manager took less processing time than Google tag (gtag.js) on 352 of them.

Each band is an app's typical processing time across the stores it was measured on. Those stores differ from app to app. That makes the result on stores that run both the fairer test. Apps found on fewer than 20 stores aren't listed yet. The list grows as more stores are checked.

All apps in the index · How we measure these numbers

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