URL Too Long: GA4 Truncation Breaks Campaign Tracking

You built the perfect campaign URL. Every parameter documented. Full campaign naming convention followed. Crystal-clear attribution.

Then you check Google Analytics 4. Your campaign data is... incomplete. Truncated. Half of your utm_campaign parameter is missing.

What happened? You hit GA4's 420-character URL limit.

The Problem: GA4 Silently Cuts Off Long URLs

What You Built

https://shop.com/products/category/subcategory/item-name?utm_source=email-marketing-platform&utm_medium=promotional-email-newsletter&utm_campaign=2024-Q1-spring-collection-launch-women-shoes-category-free-shipping-over-50-dollars&utm_content=hero-banner-image-version-A-blue-background&utm_term=keyword-womens-running-shoes-size-8

Total length: 487 characters

What GA4 Receives

https://shop.com/products/category/subcategory/item-name?utm_source=email-marketing-platform&utm_medium=promotional-email-newsletter&utm_campaign=2024-Q1-spring-collection-launch-women-shoes-category-free-shipping-over-50-do

Total length: 420 characters
Truncated: "llars&utm_content=hero-banner-image-version-A-blue-background&utm_term=keyword-womens-running-shoes-size-8"

Result:

• Campaign name incomplete: "...free-shipping-over-50-do"
• Missing utm_content entirely
• Missing utm_term entirely
• Impossible to distinguish campaigns

Why 420 Characters?

Google Analytics 4 has a hard limit:

Maximum URL length: 420 characters

This includes:

• Protocol (https://)
• Domain
• Path
• Query string (all UTM parameters)

NOT included:

• URL fragment (anchor: #section)

When your URL exceeds 420 characters, GA4 silently truncates it. No warning. No error. Just cuts it off.

What Gets Lost

Original (487 chars):
https://site.com/very/long/path?utm_source=facebook&utm_medium=cpc&utm_campaign=super-long-campaign-name-with-all-details-included-for-reporting&utm_content=ad-variant-A&utm_term=keyword
                                                                                                         ↑
                                                                               GA4 cuts here (char 420) ─┘

Stored in GA4:
https://site.com/very/long/path?utm_source=facebook&utm_medium=cpc&utm_campaign=super-long-campaign-name-with-all-details-in

You lose:

• End of utm_campaign
• All of utm_content
• All of utm_term

Real Example: E-commerce Campaign Disaster

Company: Online fashion retailer Campaign: Spring sale across 50 product categories

URL structure:

https://fashion-outlet-store.com/products/womens/shoes/running/brands/nike?utm_source=facebook-advertising-platform&utm_medium=paid-social-media-cpc&utm_campaign=2024-spring-sale-womens-running-shoes-nike-brand-25-percent-discount-free-shipping-orders-over-100-dollars&utm_content=carousel-ad-variant-blue-hero-image-model-A&utm_term=womens-nike-running-shoes-size-8

Length: 521 characters

What GA4 received (truncated at 420):

https://fashion-outlet-store.com/products/womens/shoes/running/brands/nike?utm_source=facebook-advertising-platform&utm_medium=paid-social-media-cpc&utm_campaign=2024-spring-sale-womens-running-shoes-nike-brand-25-percent-discount-free-shipping-orders-over-100-do

Impact:

• 30 different product campaigns
• All showing identical truncated names
• Impossible to separate performance
• $15,000 ad spend unattributable
• Team couldn't identify winning products

Time to discover: 3 weeks into campaign Revenue lost due to bad optimization: $22,000

How to Check If You Have This Problem

Quick Test: Character Counter

// Paste in browser console
const url = 'YOUR_CAMPAIGN_URL_HERE';
console.log('Length:', url.length);
console.log('GA4 limit: 420');
console.log('Over limit by:', Math.max(0, url.length - 420));

GA4 Test: Check Campaign Names

1. Open GA4 → Reports → Traffic acquisition

2. Look for campaigns with names that:

   • End abruptly mid-word
   • Multiple campaigns share identical names
   • Missing expected utm_content or utm_term

3. If you see truncated campaigns: you have this problem

Automated Detection

// Add to your campaign URL builder
function validateURLLength(url) {
  if (url.length > 420) {
    console.error(`URL too long: ${url.length} chars (limit: 420)`);
    console.error(`Over limit by: ${url.length - 420} characters`);
    console.error(`Truncated URL will be: ${url.substring(0, 420)}`);
    return false;
  }
  return true;
}

The Fix: Shorten Your URLs

Strategy 1: Use URL Shorteners (Quick Fix)

❌ Long URL (487 chars):
https://site.com/very/long/path?utm_source=email&utm_campaign=2024-Q1-spring-sale-category

✅ Shortened URL (85 chars):
https://bit.ly/3xY2zK4?utm_source=email&utm_campaign=2024-Q1-spring

Pros: Immediate solution Cons:

• Dependency on third-party service
• Redirect adds latency
• Some platforms block shorteners

Strategy 2: Shorten Campaign Names

❌ Long (158 chars):
utm_campaign=2024-Q1-spring-collection-launch-women-shoes-category-free-shipping-over-50-dollars

✅ Short (38 chars):
utm_campaign=2024-Q1-spring-womens-shoes

Strategy 3: Use Abbreviations

❌ Long:
utm_source=facebook-advertising-platform
utm_medium=paid-social-media-cost-per-click
utm_content=carousel-advertisement-variant-A

✅ Abbreviated:
utm_source=fb
utm_medium=paidsocial
utm_content=car-var-a

Strategy 4: Shorten Domain Paths

❌ Long:
https://online-store-ecommerce.com/products/category/subcategory/item/

✅ Short:
https://store.com/p/item/

Strategy 5: Drop Optional UTM Parameters

Only utm_source and utm_medium are required:

❌ All 5 parameters (may exceed limit):
?utm_source=x&utm_medium=y&utm_campaign=z&utm_content=a&utm_term=b

✅ Essential only (safer):
?utm_source=x&utm_medium=y&utm_campaign=z

URL Length Budget

Calculate your maximum parameter lengths:

Total budget: 420 characters

Example breakdown:
https://              8 chars
shop.com              8 chars
/products/item       14 chars
?                     1 char
utm_source=value     20 chars (max)
&utm_medium=value    20 chars (max)
&utm_campaign=value  30 chars (max)
&utm_content=value   25 chars (max)
&utm_term=value      15 chars (max)
─────────────────────────────
TOTAL:              141 chars

Remaining budget: 279 chars for longer values

FAQ

Does the 420-char limit include the fragment (#anchor)?

No. Fragments aren't sent to servers, so they don't count toward the GA4 limit.

What happens if I exceed 420 characters?

GA4 silently truncates the URL at character 420. You get incomplete campaign data with no warning.

Can I increase the GA4 URL limit?

No. The 420-character limit is hard-coded in GA4 and cannot be changed.

Do URL shorteners count toward the limit?

The SHORT URL counts (bit.ly/abc123), not the original long URL. But the UTM parameters on the short URL still count.

Will this affect my historical data?

Yes. Any historical URLs over 420 chars are already truncated in GA4. You can't recover that data.

How do I prevent this in the future?

1. Validate URL length before launching (<420 chars)
2. Use naming conventions with character limits
3. Automate validation in your URL builder
4. Monitor GA4 for truncated campaign names

Conclusion

URLs over 420 characters get truncated in Google Analytics 4, breaking campaign attribution.

The fix:

1. Check current URL lengths
2. Shorten campaign names and paths
3. Use abbreviations in UTM parameters
4. Drop optional parameters if needed
5. Validate before launching

One client lost $22,000 in optimization opportunities due to truncated campaigns. Don't let this happen to you.

Technical Reference: URL Length Exceeded Validation Rule