Dynamic Number Insertion works by placing a small piece of JavaScript on your landing page. When a visitor arrives via a Google Ad click (detected by the gclid or wbraid parameter), the script automatically swaps your static business number with a unique Google Forwarding Number (GFN).
Step 1: Create the Website Call Conversion
Navigate to Goals: Click Goals > Conversions > Summary.
Create New: Click + Create conversion action and select Phone calls.
Choose the Type: Select “Someone calls a number shown on my website“
Edit Settings:
Phone Number: Enter your business number exactly as it appears on the landing page (including spaces and brackets).
Call Length: Set a minimum duration (e.g., 60 seconds) to ensure only quality leads are counted.
Get the Tag: Google will generate a Conversion ID and Label.
Step 2: Implementation via Google Tag Manager (GTM)
Using GTM is the “best practice” for 2026 as it avoids manual code editing on every landing page.
Add Google Tag: Ensure your main Google Tag (formerly Global Site Tag) is firing on all pages.
Create Call Conversion Tag: * Tag Type: Google Ads Calls from Website Conversion.
Phone Number to Replace: Type your business number exactly as it is shown on the site.
Conversion ID & Label: Paste the values from Step 1.
Set the Trigger: Set this tag to fire on All Pages (or specifically your landing pages).
Comparison: Native Google Tracking vs. Third-Party Tools
For your technical guide, it’s important to help the reader choose the right “depth” of data.
Feature | Google Native (Free) | Third-Party (e.g., CallRail) |
Attribution | Campaign, Ad Group, Keyword | Down to the individual user session |
Call Recording | No | Yes (Transcripts & AI scoring) |
CRM Sync | Basic | Advanced (Automatic lead creation) |
Number Ownership | You use Google’s numbers | You can use your own local numbers |
Troubleshooting & Verification
The “Ad Click” Requirement: The number will only swap if the user comes from a Google Ad. To test this without spending money, add ?gclid=test to the end of your landing page URL in your browser.
The “Phone Snippet” Rule: If you are not using GTM, you must place the Phone Snippet directly after the Google Tag in the <head> of your HTML.
Checking the Status: In Google Ads, the status will remain “Unverified” until the first call is recorded. Use the Tag Assistant browser extension to verify the tag is “Firing” correctly during your tests.
Call Reporting must be enabled at the account level (Admin > Account Settings) or the dynamic swap will not function, regardless of how the tags are set up.

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