Enhanced Conversions vs Customer Match (Custom Audiences): The Complete, No-Nonsense Technical Guide

---

Most advertisers assume that Enhanced Conversions (EC) and Customer Match (CM) are nearly the same thing.

Both use hashed email addresses.
Both rely on Google’s identity graph.
Both “match” users inside Google’s ecosystem.

This leads many teams to believe that importing a list of converters is equivalent to enabling Enhanced Conversions.

It is not.

Not even close.

In reality, EC and Customer Match serve completely different roles, at different points in the funnel, and for different Google Ads systems (measurement vs targeting).

This article explains the difference once and for all.

Source: https://support.google.com/google-ads/answer/9888656

1. What Enhanced Conversions Actually Does (and Why)

Enhanced Conversions is a measurement enhancement.
It improves Google Ads’ ability to understand which click generated a specific conversion, even when cookies are blocked or degraded (ITP, ETP, adblockers, short TTL cookies).

How?
By sending hashed identifiers (email, phone, name + address) at the exact moment of the conversion.

The flow:

1. A user converts (checkout, form, signup).
2. You collect identifiers that the user willingly provides.
3. You hash them using SHA-256.
4. You attach those hashed identifiers to the conversion event.
5. Google hashes its own internal user database with the same algorithm.
6. If both hashes match → Google can link:
   • a click
   • a logged-in Google account
   • a conversion
     even without relying solely on cookies.

What EC improves:

• attribution accuracy
• conversion recovery (lost signals)
• cross-device matching
• Smart Bidding optimisation
• consistency across browsers
• deduplication across devices

What EC does not do:

• does not create an audience
• does not improve targeting
• does not generate lookalikes
• does not retarget users
• does not add users to any list

Enhanced Conversions is purely measurement.

Source: https://support.google.com/google-ads/answer/9888656

2. What Customer Match / Custom Audiences Actually Does

Customer Match is a targeting feature.

You upload a list of identifiers (emails, phone numbers, addresses, user IDs) from:

• CRM
• offline purchases
• email marketing
• loyalty teams
• subscription systems

Google hashes them (client-side or server-side), matches them to logged-in Google users, and then creates an audience segment.

Customer Match audiences can be used for:

• retargeting
• upsell
• exclusion
• suppression lists
• RLSA (Remarketing Lists for Search Ads)
• similar audiences (when available)
• customer lifecycle segmentation

What Customer Match does not do:

• does not improve attribution
• does not enhance measurement
• does not reconnect clicks to conversions
• does not fix broken tracking
• is not tied to a specific conversion event
• is not real-time
• does not influence deduplication logic

Customer Match is purely targeting.

Source: https://support.google.com/google-ads/answer/6379332

3. Why Enhanced Conversions and Customer Match Cannot Replace Each Other

Even if you import a list of your converters as a Customer Match audience, it will never replicate what Enhanced Conversions does.

Because the mechanics are fundamentally different:

Enhanced Conversions:

• works per event
• happens in real time
• tied to a click
• tied to a gclid (or wbraid/gbraid)
• tied to a timestamp
• tied to purchase_id or event_id
• improves measurement

Customer Match:

• works per user
• happens in bulk uploads
• has no click context
• no timestamp
• no attribution metadata
• no event linkage
• improves targeting

Even if both systems use SHA-256 hashing, they live in two different subsystems inside Google Ads.

One for measurement.
One for segmentation.

They do not overlap.

Source: https://support.google.com/tagmanager/answer/9205786

4. The Role of SHA-256: Matching Without Ever Knowing the Identity

Advertisers often fear sending hashed emails to Google.
“What if Google reads them? Uses them for newsletters? Uses them to track people?”

Technically impossible.

Why?

Because SHA-256 is:

• deterministic
• irreversible
• collision-resistant
• standardised
• non-decryptable
• safe for cross-system matching

Google cannot reverse the hash.
No one can.

Google only compares:

hash(identifier_you_send)
==
hash(identifier_in_its_user_database)

This equality check is what enables:

• cross-device attribution
• conversion recovery
• better Smart Bidding signals

But it never exposes the raw email to Google.

Source: https://support.google.com/tagmanager/answer/9205786

5. Timing: The Most Important Difference

This is where almost all misconceptions come from.

Enhanced Conversions timing:

• real-time
• attached to each conversion event
• part of click → user → conversion attribution

Customer Match timing:

• batch uploads
• periodic syncing
• static or semi-static segments
• no event context

Google Ads needs event-level data to optimise bidding.
A list of “people who converted” does not provide event-level data.

This is why Customer Match cannot feed Smart Bidding with the precision that Enhanced Conversions provides.

Source: https://support.google.com/google-ads/answer/9888656

6. Real-World Impact: How Each Feature Changes Performance

Impact of Enhanced Conversions:

• 5–20% more attributed conversions
• stronger bidding signals
• more stable ROAS
• improved cross-device matching
• less dependency on cookies
• higher algorithmic confidence
• reduced under-reporting on Safari

Impact of Customer Match:

• improved segmentation
• higher conversion rates on existing customers
• better suppression lists
• improved audience quality
• more relevant remarketing
• higher LTV exploitation

Enhanced Conversions = better measurement.
Customer Match = better targeting.

They complement each other.
They never replace each other.

Source: https://support.google.com/google-ads/answer/6379332

7. The Clean Comparison Table

Feature	Enhanced Conversions	Customer Match
Purpose	Measurement	Targeting
Trigger	Conversion event	Batch import
Timing	Real-time	Periodic
Uses hashed IDs	Yes	Yes
Creates audience	No	Yes
Improves attribution	Yes	No
Improves Smart Bidding	Yes	Indirectly
Tied to gclid	Yes	No
Real-time identity match	Yes	No
Use cases	Attribution, tracking	Retargeting, segmentation

Source: https://support.google.com/google-ads/answer/9888656

8. The 5-Year-Old Explanation (because simplicity helps)

Enhanced Conversions

“You tell Google exactly who converted and which click made it happen.”

Customer Match

“You give Google a list of people you want to talk to again.”

Very different goals.
Very different mechanics.
Very different outcomes.

Source: https://support.google.com/google-ads/answer/6379332

Conclusion

Enhanced Conversions and Customer Match both use hashed identifiers.
But they exist for opposite purposes:

• one improves measurement
• one improves targeting

One is real-time attribution reconstruction.
The other is audience-level segmentation.

Understanding the difference is key for:

• accurate reporting
• reliable attribution
• optimal Smart Bidding
• effective audience strategy
• privacy-compliant data flows
• cross-device consistency

They are complementary tools, not interchangeable ones.

If your tracking relies only on one of them, you’re leaving performance (and revenue) on the table.

Source: https://support.google.com/tagmanager/answer/9205786