Fix Plus Sign UTM Error: Replace + with %2B or Alternative

Your UTM has a + sign. GA4 shows inconsistent values across sessions.

Here's the 3-step fix to encode + correctly and restore consistent tracking.

The Problem

❌ INCONSISTENT:
?utm_campaign=google+ads

GA4 shows randomly:
- "google ads" (+ decoded as space)
- "google+ads" (+ kept as +)

One URL, two different campaign values

Quick Fix (3 Steps)

Step 1: Decide on Approach (30 seconds)

Choose one:

Option A: Encode + as %2B
→ Preserves + symbol in GA4

Option B: Replace with hyphen
→ Simpler, no encoding

Option C: Remove +
→ Shortest option

Step 2: Apply Fix (60 seconds)

Option A: Encode as %2B

❌ BEFORE:
?utm_campaign=google+ads

✅ AFTER:
?utm_campaign=google%2Bads

GA4 shows: "google+ads"

Option B: Replace with Hyphen

❌ BEFORE:
?utm_campaign=google+ads

✅ AFTER:
?utm_campaign=google-ads

GA4 shows: "google-ads"

Option C: Remove +

❌ BEFORE:
?utm_campaign=google+ads

✅ AFTER:
?utm_campaign=googleads

GA4 shows: "googleads"

Step 3: Test (30 seconds)

1. Visit fixed URL
2. Check browser console:
   new URL(location.href).searchParams.get('utm_campaign')
3. Verify consistent value
4. Check GA4 Real-Time

Done.

Why + Causes Inconsistency

The + symbol has dual meaning in URLs:

Historical usage: + represented spaces in early URL encoding (before %20 became standard)

Modern ambiguity: Some systems decode + as space, others keep it as literal +

Result: Same URL produces different GA4 values depending on:

• Browser version
• Platform click redirects
• Server-side URL processing
• Client-side JavaScript parsing

This creates data fragmentation where identical campaign URLs report under multiple campaign names.

Automated Fix Script

function fixPlusSign(url, method = 'encode') {
    const urlObj = new URL(url);
 
    ['utm_source', 'utm_medium', 'utm_campaign', 'utm_content', 'utm_term'].forEach(key => {
        let value = urlObj.searchParams.get(key);
 
        if (value && value.includes('+')) {
            switch(method) {
                case 'encode':
                    // Encode + as %2B
                    value = value.replace(/\+/g, '%2B');
                    break;
                case 'hyphen':
                    // Replace + with -
                    value = value.replace(/\+/g, '-');
                    break;
                case 'remove':
                    // Remove + entirely
                    value = value.replace(/\+/g, '');
                    break;
            }
 
            urlObj.searchParams.set(key, value);
        }
    });
 
    return urlObj.toString();
}
 
// Usage
const broken = 'site.com?utm_campaign=google+ads';
 
console.log(fixPlusSign(broken, 'encode'));
// site.com?utm_campaign=google%2Bads
 
console.log(fixPlusSign(broken, 'hyphen'));
// site.com?utm_campaign=google-ads
 
console.log(fixPlusSign(broken, 'remove'));
// site.com?utm_campaign=googleads

Common Scenarios & Fixes

Scenario 1: Product Names

Product: C++ Programming

❌ INCONSISTENT:
utm_content=C++

✅ FIX Option 1:
utm_content=C%2B%2B
→ GA4: "C++"

✅ FIX Option 2:
utm_content=cpp
→ GA4: "cpp"

Scenario 2: Brand Names

Brand: Google+

❌ INCONSISTENT:
utm_source=google+

✅ FIX Option 1:
utm_source=google%2B
→ GA4: "google+"

✅ FIX Option 2:
utm_source=googleplus
→ GA4: "googleplus"

Scenario 3: Multiple + Symbols

Campaign: C++ for C# Developers

❌ INCONSISTENT:
utm_campaign=c++for-c#-devs

✅ FIX:
utm_campaign=cpp-for-csharp-devs
→ Simple, readable, no encoding

Scenario 4: Mathematical Operators

Campaign: 1+1 Sale

❌ INCONSISTENT:
utm_campaign=1+1_sale

✅ FIX Option 1:
utm_campaign=1%2B1_sale
→ GA4: "1+1_sale"

✅ FIX Option 2:
utm_campaign=bogo_sale
→ More descriptive anyway

Bulk Fix Script

// Fix multiple URLs at once
function bulkFixPlusSign(urls, method = 'encode') {
    return urls.map(url => {
        try {
            return fixPlusSign(url, method);
        } catch (error) {
            console.error(`Failed to fix: ${url}`, error);
            return url;
        }
    });
}
 
// Usage
const urls = [
    'site.com?utm_campaign=google+ads',
    'site.com?utm_source=bing+search',
    'site.com?utm_content=c++'
];
 
const fixed = bulkFixPlusSign(urls, 'encode');
console.log(fixed);
// All + encoded as %2B

Platform-Specific Application

Google Ads

Tracking Template:
{lpurl}?utm_campaign=google%2Bads&gclid={gclid}
                          ↑
                    Encode + as %2B

Facebook Ads

URL Parameters:
utm_source=facebook&utm_campaign=product%2Bads
                                      ↑
                                Encode + as %2B

Microsoft Ads

Tracking Template:
{lpurl}?utm_campaign=bing%2Bsearch&msclkid={msclkid}
                         ↑
                   Encode + as %2B

Email HTML

<a href="site.com?utm_campaign=product%2Bpromo&utm_source=email">
    Shop Now
</a>

Validation After Fix

function validatePlusFix(url) {
    const urlObj = new URL(url);
    const rawQuery = url.split('?')[1] || '';
 
    // Check if any unencoded + remains in UTM values
    const utmParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_content', 'utm_term'];
 
    const issues = utmParams
        .filter(param => {
            const paramPattern = new RegExp(`${param}=([^&]*)`);
            const match = rawQuery.match(paramPattern);
            return match && match[1].includes('+') && !match[1].includes('%2B');
        })
        .map(param => ({
            parameter: param,
            issue: 'Contains unencoded +'
        }));
 
    return {
        valid: issues.length === 0,
        issues
    };
}
 
// Usage
const url = 'site.com?utm_campaign=google%2Bads';
const result = validatePlusFix(url);
 
if (result.valid) {
    console.log('✅ All + signs properly encoded');
} else {
    console.log('❌ Issues found:', result.issues);
}

Decision Matrix

Testing Checklist

After fixing:

✅ Visual check
   URL contains %2B (or alternative), not raw +

✅ Browser test
   new URL('url').searchParams.get('utm_campaign')
   Shows consistent value

✅ Cross-browser test
   Chrome, Firefox, Safari, Mobile
   All show same value

✅ GA4 Real-Time test
   Campaign appears with expected value
   No data fragmentation

✅ Historical comparison
   Compare to past campaign names
   Ensure no duplicates created

Real-World Example: Tech Product Launch

Company: Online learning platform Product: "C++ Mastery Course" Campaign: Google Ads + Facebook Ads Budget: $12,000

Broken URLs:

Google: site.com/cpp?utm_campaign=c++_mastery&utm_source=google
Facebook: site.com/cpp?utm_campaign=c++_mastery&utm_source=facebook

Result in GA4:

• Campaign variations showing as:
  • "c _mastery" (+ decoded as spaces)
  • "c++_mastery" (+ preserved)
• Data split across 2 campaign names
• Unable to calculate true ROI

Fixed URLs (2 minutes):

Google: site.com/cpp?utm_campaign=cpp_mastery&utm_source=google
Facebook: site.com/cpp?utm_campaign=cpp_mastery&utm_source=facebook

Result:

• Single unified campaign: "cpp_mastery"
• Accurate ROI calculation
• Clear attribution across platforms

FAQ

Should I always encode + as %2B?

If you need literal + in GA4, yes. Otherwise, consider simpler alternatives (hyphen, remove). For brand names like Google+ or product names like C++, encoding preserves the original branding.

What if + appears multiple times?

Encode or replace ALL occurrences:

value.replace(/\+/g, '%2B') // All + → %2B

Never partially encode—this creates even more fragmentation.

Will this break existing campaigns?

If changing mid-campaign, you'll create new campaign value in GA4. Historical data remains under old value. Better to fix before launch. For active campaigns, consider finishing the campaign with existing URLs and fixing for next campaign.

Can I use + for spaces?

Not recommended. Use %20 or underscores for better reliability. The + symbol's dual meaning (space vs literal plus) causes too much inconsistency across platforms.

How do I find all URLs with unencoded + signs?

Export campaign URLs, use this regex pattern:

const hasUnencodedPlus = url.match(/[?&]utm_[^=]+=([^&]*\+[^&]*)/);

Or in Google Sheets:

=IF(ISNUMBER(SEARCH("+",A1)),"Contains +","OK")

Does this affect URL shorteners?

Most URL shorteners (Bitly, TinyURL) handle encoding automatically, but it's safer to encode before shortening to ensure consistency.

What about + in the domain or path?

Domain names cannot contain +. In URL paths, + should be avoided or encoded as %2B for consistency.

Can email platforms handle + signs correctly?

Email platforms vary. Some auto-encode, others don't. Always manually encode to ensure consistency across Mailchimp, Klaviyo, SendGrid, etc.

How does this interact with server-side tracking?

Server-side tracking (via Measurement Protocol) requires consistent encoding. If your server decodes + as space but GA4 keeps it literal, you'll have duplicate sessions. Always encode as %2B for server-side implementations.

What if my CMS or marketing platform adds + automatically?

Check your platform's URL encoding settings. Disable automatic + insertion if possible. If not, use the JavaScript fix script to clean URLs before they reach GA4.

Conclusion

Fix + in UTM parameters in 3 steps:

1. Choose approach: encode, replace, or remove
2. Apply fix using script or manual edit
3. Test in browser and GA4

❌ utm_campaign=google+ads (inconsistent)
✅ utm_campaign=google%2Bads (encoded)
✅ utm_campaign=google-ads (alternative)

Encode + as %2B for consistent tracking across all platforms.

Technical Reference: Plus Sign in Value Validation Rule