Blog/Google Ads
How to set up Google Ads conversion tracking — and why most accounts get it wrong.
Conversion tracking tells Google's Smart Bidding what to optimise toward. If it's broken, the algorithm is flying blind — spending your budget on clicks with no feedback signal. The most common mistakes: importing GA4 goals as primary conversions, setting micro-conversions (page views, video plays) as primary, and never testing after a site redesign. This guide covers setup via GTM, primary vs secondary settings, and how to verify it all works.
Ahmed Ashraf
Founder, Traffiy · April 2026 · Google Premier Partner
“I've audited hundreds of accounts. Broken conversion tracking is the single most common reason Smart Bidding fails. Fix the measurement first — everything else is secondary.”
— Ahmed Ashraf · $100M+ in budgets managed
1 in 3
Accounts have inaccurate conversion tracking — missing conversions, duplicate tracking, or soft conversions set as primary
30–50
Conversions per month needed for Smart Bidding to optimise effectively — below this, manual bidding outperforms
7 days
Typical click-to-conversion window for B2B — most leads that convert from a click do so within a week
The four conversion types
What Google Ads can measure — and which one to set as primary.
Website actions
PrimaryForm submissions, purchases, click-to-call, page visits. Most important — set your highest-value action as primary.
Phone calls
Calls from call assets, on-site number clicks, or calls to a Google forwarding number. Important for local and service businesses.
App installs & in-app
App downloads and in-app events (purchase, sign-up). Requires linking to Firebase or third-party attribution.
Store visits
Estimated visits to physical locations after an ad click. Google estimates this from location data — not a precise count.
Step-by-step setup
Setting up website conversion tracking via Google Tag Manager.
Create the conversion action
In Google Ads: Tools → Conversions → New conversion action → Website. Name it precisely (e.g., 'Contact Form Submit — Homepage', not just 'Form'). Set the category (Lead, Purchase, etc.), value (fixed or variable), count (One per click for leads, Every for purchases), and conversion window (30 days for B2B, 7 days for eCommerce).
Set primary vs secondary correctly
In the conversion action settings, set your actual purchase or lead form as 'Primary — used for bidding'. Micro-conversions (newsletter sign-up, scroll depth, video view) must be set to 'Secondary — not used for bidding'. This is one of the most common mistakes in accounts I audit — Smart Bidding chasing page views.
Install via Google Tag Manager
In GTM: New Tag → Google Ads Conversion Tracking → paste Conversion ID and Conversion Label from Google Ads. Set trigger to your thank-you page URL (e.g., '/thank-you' or '/order-confirmation'). Use Page URL trigger, not Page View. Publish the container.
Test with GTM Preview mode
Click Preview in GTM, navigate to your site, complete a test conversion. In the GTM debugger, confirm the 'Google Ads Conversion Tracking' tag shows as 'Fired' on the correct page. Also check in Google Ads → Tools → Conversions — the 'Last conversion' date should update within a few hours.
Set the attribution model
Go to Tools → Conversions → click your conversion action → Attribution model. Data-driven is recommended if you have 300+ conversions in 30 days — it distributes credit across touchpoints based on actual path data. Below that, use Last click. Never use First click for optimisation — it credits awareness, not intent.
| Mistake | What It Causes | Fix |
|---|---|---|
| GA4 goals as primary | Inflated conversion numbers, soft signals driving bidding | Use Google Ads tag directly for primary conversions |
| Micro-conversions as primary | Smart Bidding chases page views, not purchases | Set to secondary; only real business outcomes as primary |
| Never tested after site changes | Tracking silently breaks; bidding goes blind | Test every conversion with Tag Assistant after any deploy |
| Duplicate conversion actions | Conversions counted 2-3x; CPA looks lower than it is | Audit Tools → Conversions; remove or pause duplicates |
FAQ
Common questions about conversion tracking.
What are the 4 types of Google Ads conversions?+
Google Ads tracks four conversion types: website actions (form submits, purchases, page views), phone calls (from call extensions or on-site number clicks), app installs and in-app actions, and store visits (for businesses with physical locations, estimated from Google Maps data). For most advertisers, website actions are the primary focus.
What is the difference between primary and secondary conversions in Google Ads?+
Primary conversions are what Smart Bidding optimises toward — these should be your most valuable actions (purchases, qualified form submissions). Secondary conversions are tracked for reporting only and don't influence bidding. Most accounts incorrectly set micro-conversions like page views or video plays as primary, which causes Smart Bidding to optimise toward soft signals instead of real business outcomes.
Should I import GA4 goals into Google Ads as conversions?+
Use GA4 imports with caution. GA4 uses last-click attribution by default and counts each session as a conversion — this can inflate your numbers. For primary conversions, use the Google Ads tag directly (via GTM) with the correct conversion window set. Use GA4 imports as secondary conversions for reporting context, not as the signal Smart Bidding optimises toward.
How do I verify my conversion tracking is working?+
Three methods: (1) Google Tag Assistant — install the Chrome extension and complete a real conversion on your site to confirm the tag fires. (2) GTM Preview mode — connect GTM to your site in preview mode and check which tags fire on your thank-you page or purchase confirmation page. (3) Diagnostics tab — in Google Ads, go to Tools → Conversions, click into a conversion action, and check the Diagnostics tab for errors or warnings.
What conversion window should I set for B2B campaigns?+
For B2B with longer sales cycles, use a 30-day click conversion window and a 1-day view-through window. The default 30-day click window captures most B2B research journeys. Some enterprise deals run longer — in which case 90 days is appropriate. For eCommerce, 7-day click is usually sufficient since purchase intent resolves quickly.
Ahmed Ashraf — Founder, Traffiy
10+ years in paid media. $100M+ in budgets managed across Meta, Google, and TikTok. Google Premier Partner — top 3% globally. Every article on this blog is written from direct experience managing real campaigns.
Want us to audit your conversion tracking setup?
Traffiy fixes conversion tracking as part of every account audit. We verify every conversion action fires correctly before touching bids or keywords.