What Is an FBCLID? Facebook Click Identifier Explained

An FBCLID (Facebook Click Identifier) is a unique tracking parameter that Meta automatically appends to outbound URLs when a user clicks a link on Facebook or Instagram. It serves as Meta’s equivalent of Google’s GCLID — a mechanism to connect ad clicks to downstream conversions.

For The Upload Offline Conversions App (TUOCA), the FBCLID is a key piece of the Meta Conversions API (CAPI) integration, enabling offline conversions from phone calls, booked jobs, and completed services to be attributed back to the Facebook or Instagram ad that initiated the customer journey.

How FBCLID Works

When someone clicks a link on Facebook or Instagram — whether it’s an ad, an organic post, or a shared link — Meta appends an fbclid parameter to the destination URL:

https://yourwebsite.com/landing-page?fbclid=IwAR3x7J2KpQ9_vNmHbLcR8tZ1eY5kA

The Attribution Flow

1. User clicks ad on Facebook/Instagram — Meta generates a unique FBCLID
2. FBCLID appended to URL — The parameter is added to the destination URL
3. Facebook Pixel reads FBCLID — The pixel on your website reads the FBCLID and stores it in a first-party cookie (_fbc)
4. User converts (online or offline) — The conversion event happens on your site, over the phone, or in person
5. Conversion data sent to Meta — Via Pixel (online) or Conversions API (offline), the FBCLID/fbc is included
6. Meta attributes the conversion — Meta matches the click to the conversion

FBCLID vs. fbc: Understanding the Difference

This is a common source of confusion. Meta uses two related but distinct values:

Parameter	Example	Where It Appears	Used In
FBCLID	IwAR3x7J2KpQ9_vN...	URL query string (?fbclid=)	URL parameter
fbc	fb.1.1714000000.IwAR3x7J2KpQ9_vN...	_fbc cookie, Conversions API	CAPI uploads

The fbc parameter is derived from the FBCLID but includes additional metadata:

fb.1.{creation_timestamp}.{fbclid}

• fb — Identifier prefix
• 1 — Version number
• {creation_timestamp} — Unix timestamp (milliseconds) when the cookie was set
• {fbclid} — The original FBCLID value

When uploading offline conversions via the Conversions API, Meta expects the fbc parameter, not the raw FBCLID. TUOCA handles this conversion automatically.

FBCLID Characteristics

Property	Value
URL parameter	fbclid
Typical length	30–60 characters
Format	Alphanumeric string, often starting with IwAR
Added to	All outbound links from Facebook/Instagram (ads and organic)
Validity for offline conversions	7 days (via CAPI)
Can be disabled?	No (for ads)

The 7-Day Window

A critical difference between FBCLID and GCLID is the event window:

• GCLID: 90 days
• FBCLID/fbc: 7 days (standard), up to 28 days for some event types

This means offline conversions must be uploaded to Meta within 7 days of the ad click. For service businesses with longer sales cycles, this is often too short. The solution: use Enhanced Matching with hashed PII alongside the fbc parameter.

FBCLID for Offline Conversion Tracking

Why FBCLID Alone Isn’t Enough

Unlike Google Ads, where the GCLID is the primary matching mechanism, Meta’s Conversions API relies more heavily on user data matching (hashed email, phone) than on the FBCLID/fbc parameter. This is because:

1. Meta’s attribution is people-based, not cookie-based
2. The FBCLID window is only 7 days, making it impractical for most service business sales cycles
3. Enhanced Matching with hashed PII provides better cross-device attribution

Recommended Approach

Send both the fbc parameter and hashed PII:

{
  "data": [{
    "event_name": "Purchase",
    "event_time": 1714502400,
    "action_source": "system_generated",
    "user_data": {
      "fbc": "fb.1.1714000000.IwAR3x7...",
      "em": ["a8b14f04b2..."],
      "ph": ["d4f5c3b1e7..."]
    },
    "custom_data": {
      "value": 4500.00,
      "currency": "USD"
    }
  }]
}

Capturing FBCLID on Your Website

Hidden Form Field

<input type="hidden" name="fbclid" id="fbclid" value="">
<script>
  const params = new URLSearchParams(window.location.search);
  const fbclid = params.get('fbclid');
  if (fbclid) {
    document.getElementById('fbclid').value = fbclid;
  }
</script>

Call Tracking Tools

CallRail and CallTrackingMetrics capture the FBCLID from the referring URL when a tracked call occurs. Use the Click ID Tester tool to verify FBCLID capture on your pages.

How TUOCA Uses FBCLID

TUOCA’s Meta integration handles FBCLID processing end-to-end:

1. Extraction — Pulls the FBCLID or fbc value from connected data sources
2. Format conversion — Converts raw FBCLID to fbc format if needed
3. PII collection — Gathers email and phone for Enhanced Matching
4. Normalization & hashing — Normalizes PII and applies SHA-256 hashing per Meta’s requirements
5. CAPI upload — Sends the complete event (fbc + hashed PII + value) to the Conversions API
6. Deduplication — Uses event_id to prevent duplicate conversions

FBCLID vs. Other Click Identifiers

Platform	Parameter	Validity	Primary Matching
Google Ads	GCLID	90 days	Click-level (deterministic)
Google (privacy)	WBRAID/GBRAID	90 days	Modeled (aggregated)
Meta	FBCLID/fbc	7 days	People-based + click
Microsoft	MSCLKID	90 days	Click-level (deterministic)
TikTok	TTCLID	28 days	Click-level + user data

The most important takeaway: Meta’s 7-day window is uniquely short. If your business has a sales cycle longer than 7 days, you must supplement the FBCLID with Enhanced Matching via hashed PII. TUOCA handles this automatically by always sending both identifiers when available.