Google Ads conversion tags in Google Tag Manager

#01Conversion Linker first

According to Google Tag Manager Help, Conversion Linker tags detect ad click information in landing page URLs and store it in first-party cookies. Create:

1. Tag type Conversion Linker.
2. Trigger All Pages.
3. Name Conversion Linker - All Pages.
4. Preview on a URL that includes a test gclid query param; confirm the tag fires.

If journeys cross domains, enable linking across domains and list domains (lesson 15).

#02Google Ads Conversion Tracking tag

1. In Google Ads, create or open the conversion action and choose the Tag Manager instructions.
2. Copy Conversion ID and Conversion Label into GTM Constants.
3. Tags → New → Google Ads Conversion Tracking.
4. Paste ID and label (or send_to style fields as shown).
5. Optional: conversion value, currency, transaction ID (for purchases — critical for dedupe).
6. Trigger: Custom Event generate_lead or your Page Path thank-you rule.
7. Preview and publish.

For purchases, always pass a unique transaction ID so Google can deduplicate reloads of the receipt page.

#03Choosing triggers for Ads tags

#04Enhanced conversions note

User-provided data / enhanced conversions improve match rates. Configure them carefully (lesson 10). As of Google Ads Help notes in 2026, enhanced conversions for web and leads have been moving to a unified setting (migration messaging referenced an April 2026 change). Confirm the toggle state in your Ads account rather than following outdated "web vs leads" screenshots.

#05Testing without polluting production

• Use Ads conversion action “Include in conversions” carefully for tests.
• Add a ?gtm_preview workflow and verify with Tag Assistant.
• For known clicks, use Google’s conversion debugging / Tag Assistant coverage.
• Keep staging hostnames out via exception triggers.

#06Worked example: Ledgerline Ads tag

Ledgerline is a fictional accounts-payable software company. Details are illustrative.

Ledgerline’s old conversion action fired on /thanks with a value of 1. After a site redesign, /thanks became /demo/confirmation and conversions dropped to near zero for ten days while spend continued. They rebuilt the tag on generate_lead, kept transaction-less leads without a value (or used a static predicted value agreed with finance), and added Linker which had been missing.

Walkthrough

1. Add Conversion Linker on All Pages; publish if missing.
2. Create Constants for ID and label.
3. Create the Conversion Tracking tag on your proven Custom Event.
4. Exception: block when lut - hostname to env ≠ production.
5. Click a live ad or use a test click URL; complete the conversion; confirm in Ads’ conversion diagnostics for that action.
6. Cross-check GA4 key event counts the same day.

#07Common mistakes

• No Linker tag.
• Two primary conversion actions for one form.
• Value = revenue on a lead form without a model (Sales freaks out; bidding chases fake ROAS).
• Firing on all form starts, not successes.
• Publishing on Friday evening without monitoring Monday.

#08Call and other conversion types

This lesson focuses on website tags. Call conversions, app conversions and store visits use different setups inside Google Ads. Do not shoehorn them into a Page Path trigger. Keep website actions in GTM; configure call reporting in Ads.

#09Value rules and lead gen

If you assign a static conversion value to demo requests (for example 50 EUR), write down who owns the number and when it gets revised. Random values create false ROAS confidence. Some teams keep lead conversions without values and optimise to maximise conversions instead — also valid.

#10Cross-account and MCC notes

Agencies operating under an MCC must confirm the conversion action lives in the client account they expect. GTM Constants with the wrong AW ID are a silent failure mode — Preview shows a tag fire; Ads shows nothing in the client.

#11Enhanced attributions still need a fire

Whether you use data-driven attribution in Ads or import from GA4, something must still fire on the user action. Attribution models do not invent events. Broken GTM triggers remain broken under any model.

#12Floodlight / CM360 aside

Campaign Manager 360 Floodlight tags are a different animal. If your organisation uses Floodlight, keep them in a clearly named folder and involve the platform team — do not casually duplicate Floodlight and Ads conversion tags for the same action without a plan.

#13Phone numbers on landing pages

If click-to-call is material, configure call conversions in Google Ads properly. A GTM click trigger on tel: links can support analytics (click_to_call) but is not a complete Ads call conversion setup by itself.

#14Conversion Linker placement

Keep Conversion Linker on All Pages (subject to consent). Without it, click IDs may not persist correctly into conversion time on many sites. Preview should show the Linker firing early. If someone paused it "to reduce tags", restore it before you debug "Ads conversions missing gclid".

#15Primary vs secondary in practice

• Primary: the action Smart Bidding should optimise toward (usually qualified lead or purchase).
• Secondary: observed for diagnostics, not for bidding.

Importing every scroll and video start as primary is how accounts learn the wrong goal. Coordinate with the conversion goals lesson.

#16Duplicate conversion detection

In Google Ads conversion actions list, search for your page or event name. Two website conversions for the same thank-you URL — one from an old hard-coded tag and one from GTM — is a frequent agency inheritance issue. Pause the legacy action after confirming GTM fires, then watch for a week before deleting.

#17Testing with click IDs

When possible, click a real (or draft) ad, land with gclid, convert, and confirm the conversion appears attributed. Pure Preview without a click ID validates the tag fire but not the full Ads join. Document both levels of QA in the version note.

#18Remarketing and conversion tags together

Conversion tags and remarketing / audience tags often share the Conversion Linker but not the same triggers. Keep remarketing on broad page triggers (with consent) and conversions on success events. Mixing "fire remarketing only on thank-you" usually underfills audiences; firing conversions on All Pages creates junk conversions.

#19Agency handoff checklist

When an agency builds Ads tags in your GTM:

1. They use your AW ID Constant, not theirs.
2. Conversion action lives in the correct client account.
3. Version note names the Ads action ID.
4. You Preview with a client user before publish.
5. You own publish rights.

Never give blanket publish on production to every contractor seat.

#20Try it yourself

Inventory every Google Ads conversion action that receives website tags. For each, note the GTM tag name, trigger and whether a GA4 import also exists. Resolve duplicates.

#21Quick quiz

1. What does Conversion Linker store?

Answer: Ad click information in first-party cookies (and related storage) so conversions can be attributed.

2. Why pass transaction ID on purchase conversions?

Answer: So Google can deduplicate reloads and repeated tags for the same order.

3. Why can thank-you URL triggers fail suddenly?

Answer: CMS/redirect/slug changes stop matching the Page Path rule.

#22What should you check before the next lesson?

• Conversion Linker live.
• At least one Ads conversion tag mapped to a reliable trigger.
• Duplicate primary actions resolved.

Previous: GA4 key events and Ads import. Next: Enhanced conversions in GTM. Or return to the GTM for Marketers track. Related: Enhanced conversions and Data Manager.

#23Common questions

Need Conversion Linker? Yes, Google recommends it on potential landing pages.

ID vs label? Account tag ID vs specific conversion action label.

Thank-you vs data layer? Data layer is more reliable.