What Is Enhanced Conversions? Google's First-Party Data Matching for Offline Conversion Tracking

Enhanced Conversions is a feature across major ad platforms that uses hashed first-party data — email addresses, phone numbers, names — to match conversions to ad clicks without relying on third-party cookies or click identifiers like GCLIDs.

For The Upload Offline Conversions App (TUOCA), Enhanced Conversions are a critical fallback and complement to traditional click ID-based matching. When a GCLID expires, wasn’t captured, or the user converts on a different device, Enhanced Conversions provide an alternative matching path using the PII your business already collects.

Why Enhanced Conversions Exist

The advertising industry is undergoing a fundamental shift away from third-party cookies and cross-site tracking:

• iOS 14.5 (ATT): Apple’s tracking prompt asks the person to allow or refuse tracking across apps. Many people refuse, and the landing URL may then carry a WBRAID or GBRAID instead of a GCLID. Store the ID that is actually on the URL.
• Chrome Privacy Sandbox: Google is restricting third-party cookies in Chrome
• Browser restrictions: Firefox, Safari, and Brave block third-party cookies by default
• Regulatory pressure: GDPR, CCPA, and other privacy laws restrict tracking

These changes make traditional click ID-based tracking less reliable. Click IDs like GCLIDs depend on browser cookies to persist, and when cookies are blocked or cleared, the click ID is lost.

In 99 conversion-lift studies from April 2024 through April 2025, Google found an average 8% incremental ROAS on Search for advertisers who bid to conversion value and use enhanced conversions. Google’s October 2025 article also said early adopters saw a median conversion-rate increase of 5% on Search and 17% on YouTube. Those are changes in reported results, not a match rate for an email or a phone.

Enhanced Conversions solve this by matching on first-party data you already own — the email address, phone number, or name that a customer voluntarily provides when they fill out a form, call your business, or make a purchase.

How Enhanced Conversions Work

The Matching Process

1. User clicks your ad — Google records the click and associates it with the user’s Google account (which is linked to their email, phone, etc.)
2. User provides PII — The prospect submits a form with their email, calls your business, or provides their contact info through any channel
3. You hash the PII — Using SHA-256, you hash the email/phone/name after normalizing it
4. You upload the hash + conversion — Send the hashed PII, conversion action, timestamp, and value to Google
5. Google matches — Google independently hashes its records of the same user’s PII and compares. If the hashes match, the conversion is attributed to the original click

The critical insight: Neither party ever sends raw PII to the other. Both sides hash independently and match on the hash values.

Enhanced Conversions for Web vs. for Leads

You turn enhanced conversions on once. The website tag and the later job upload both use that setting. You are not picking between two products.

Feature	Enhanced Conversions for Web	Enhanced Conversions for Leads
Purpose	Improve online conversion measurement	Match offline/CRM conversions to clicks
Implementation	Google tag (gtag.js) supplement	Server-side upload (API/CSV)
When PII is collected	At online conversion time	At lead creation time
When conversion is reported	Immediately (online event)	Later, when lead converts offline
GCLID required?	No. The tag already saw the click.	Send it when you have it. Hashed data covers the miss.
Used by TUOCA?	No	Yes

Enhanced Conversions for Leads — How TUOCA Uses Them

In the TUOCA workflow:

1. A prospect clicks your ad and calls your business via CallRail/CallTrackingMetrics
2. The call tracking tool records the caller’s phone number and (if available) the GCLID
3. The lead enters your CRM (ServiceTitan, Jobber, etc.)
4. Days/weeks later, the lead becomes a booked job
5. TUOCA fetches the conversion data, normalizes the phone number to E.164, hashes it with SHA-256, and uploads it alongside any available GCLID
6. Google matches using GCLID first (highest accuracy), then falls back to hashed PII matching

The advantage: Even if the GCLID wasn’t captured or has expired, the hashed phone number provides a matching path. Combined with a GCLID, match rates can exceed 90%.

Supported Identifiers

Google Ads

Identifier	Parameter	Normalization	Match Quality
Email address	hashed_email	Lowercase, trim whitespace	★★★★★
Phone number	hashed_phone_number	E.164 format (+1XXXXXXXXXX)	★★★★
First name	hashed_first_name	Lowercase, trim	★★★
Last name	hashed_last_name	Lowercase, trim	★★★
Street address	hashed_street_address	Lowercase, trim	★★
City	city	Lowercase, trim	★★
State	state	2-letter abbreviation	★★
Postal code	postal_code	First 5 digits (US)	★★
Country	country	ISO 2-letter	★★

Best practice: Send as many identifiers as you have. More signals = higher match rates.

Cross-Platform Equivalents

Enhanced Conversions isn’t unique to Google. Other platforms have similar systems:

Platform	Feature Name	Matching Method
Google Ads	Enhanced Conversions for Leads	SHA-256 hashed PII
Meta	Enhanced Matching (CAPI user_data)	SHA-256 hashed PII
Microsoft Ads	Enhanced Conversions	SHA-256 hashed PII
TikTok	Events API user data	SHA-256 hashed PII

The normalization rules differ slightly between platforms (e.g., Meta doesn’t strip Gmail dots; Google does). TUOCA handles platform-specific normalization automatically.

SHA-256 Hashing

SHA-256 (Secure Hash Algorithm 256-bit) is the only accepted hashing algorithm for Enhanced Conversions across all platforms. Do not use MD5, SHA-1, Base64, or any other encoding.

How to Hash Correctly

Step 1: Normalize the data

Email:  "  John.Doe@Gmail.COM  "  →  "john.doe@gmail.com"
Phone:  "(555) 123-4567"          →  "+15551234567"
Name:   "  John  "                →  "john"

Step 2: Apply SHA-256 hash

"john.doe@gmail.com"  →  "e8b6...a4f2" (64-character hex string)
"+15551234567"        →  "d4f5...b3c1"
"john"                →  "a8cf...2e91"

Common mistakes that break matching:

• Hashing before normalizing (the hash of “John” ≠ the hash of “john”)
• Using MD5 or SHA-1 instead of SHA-256
• Including whitespace in the input
• Phone numbers without country code
• Not removing non-digit characters from phone numbers

For quick hashing, use our SHA-256 Hasher tool. For phone number formatting, use the E.164 Formatter.

Matching Windows

Platform	GCLID/Click ID Window	Enhanced Conversions Window
Google Ads	90 days after the click	63 days after the click
Meta	7 days after the event	7 days after the event (62 days for a physical-store sale)
Microsoft	90 days	90 days (a hash does not stretch this)
TikTok	Keep the click ID at least 28 days	The attribution window you set

Google keeps a GCLID for 90 days after the click, so a job closed on day 75 can still be uploaded and the same job closed on day 91 cannot. A hashed email or phone matches for 63 days after the click, and from day 64 through day 90 only the GCLID still matches. For a sale that will close after day 63, upload an earlier milestone, such as a qualified lead on day 30, while the hash still matches.

Meta rejects a Conversions API request when the event happened more than 7 days before you send it, so a booking from Monday has to be uploaded by the next Monday, unless it is a physical-store sale, which Meta asks you to send within 62 days.

Microsoft Advertising rejects an offline conversion whose time is more than 90 days before the upload and will not count one more than 90 days after the click, so keep the MSCLKID for those 90 days: a sale on August 1 can be uploaded on October 20, and a job that closes 100 days after the click cannot be counted even if you upload it that day.

TikTok asks you to keep the click ID for at least 28 days and expires it on the attribution window you set, so keep the ID from a March 1 click through at least March 29 and send the job while that window is still open.

Improving Match Rates

Low match rates are the most common issue with Enhanced Conversions. Here’s how to diagnose and improve them:

Diagnostic Checklist

1. Are you normalizing before hashing? The hash of John@EMAIL.com ≠ john@email.com
2. Are phone numbers in E.164 format? Must include country code: +15551234567
3. Are you using SHA-256? MD5 and SHA-1 will produce zero matches
4. Are you sending multiple identifiers? Email + phone + name gives much higher match rates than email alone
5. Is the data fresh? Users may have changed their email since clicking the ad
6. Are you within the matching window? A hashed email or phone matches for 63 days after the click, and from day 64 through day 90 only the GCLID still matches. Meta rejects a Conversions API request when the event happened more than 7 days before you send it, so a booking from Monday has to be uploaded by the next Monday, unless it is a physical-store sale, which Meta asks you to send within 62 days.

Expected Match Rates

What you send	What it does
GCLID only	Matches the click through day 90. A missing click ID is a miss.
Email only (hashed)	Can match a signed-in Google account. One field, one chance.
Phone only (hashed)	A second chance when the email was never on a Google account.
Email + phone (hashed)	Two fields on the same row.
GCLID + email + phone	The click ID plus the hash. Google does not publish a match rate for this. Read the diagnostics card.

TUOCA’s approach: When both a GCLID and PII are available, TUOCA sends both. Google uses the GCLID for primary matching and falls back to hashed PII when needed, maximizing match rates.

How TUOCA Handles Enhanced Conversions

TUOCA automates the entire Enhanced Conversions pipeline:

1. Data extraction — Pulls lead data from connected sources (CallRail, CallTrackingMetrics, ServiceTitan, Jobber, webhooks)
2. PII identification — Automatically identifies email, phone, and name fields in the source data
3. Normalization — Applies platform-specific normalization rules (lowercasing, trimming, E.164 formatting)
4. Hashing — SHA-256 hashes all PII fields
5. GCLID pairing — When a GCLID is available (from call tracking), sends it alongside hashed PII for maximum match rates
6. Upload — Sends the normalized, hashed, deduplicated data to the destination platform
7. Error handling — Catches and logs INVALID_USER_IDENTIFIER errors, which typically indicate normalization issues

This entire pipeline runs automatically on every relay execution. You configure the field mappings once, and TUOCA handles normalization and hashing on every upload.

Getting Started with Enhanced Conversions

1. Enable Enhanced Conversions in Google Ads — Settings → Measurement → Enhanced Conversions → Turn On
2. Accept the terms — Customer data terms must be accepted
3. Verify your data sources collect PII — Email and phone at minimum
4. Set up TUOCA — Connect your source and destination, map PII fields
5. Monitor match rates — Check the Diagnostics report in Google Ads → Tools → Data Manager
6. Optimize — Send additional PII fields to improve matching