Fix Unencoded Ampersand in UTM: 3-Step Quick Guide

Your UTM campaign name has an &. GA4 shows truncated data.

Here's the 3-step fix to encode ampersands and restore complete tracking.

The Problem

❌ BROKEN:
?utm_campaign=save&win

Parsed as:
utm_campaign = "save"
win = "" (interpreted as separate parameter)

GA4 shows: "save"
Missing: "&win"

Quick Fix (3 Steps - Under 2 Minutes)

Step 1: Find the Ampersand (30 seconds)

Look at your URL and find the & that's INSIDE a parameter value:

?utm_campaign=save&win&utm_medium=cpc
              ↑   ↑    ↑
          Part of   Should be
          value     separator

Find this & (in value) → needs encoding

Step 2: Replace with %26 (60 seconds)

❌ BEFORE:
?utm_campaign=save&win&utm_medium=cpc

✅ AFTER:
?utm_campaign=save%26win&utm_medium=cpc
              ↑      ↑
         Encoded as %26

Rule: Replace & INSIDE parameter values with %26. Leave & BETWEEN parameters.

Step 3: Test (30 seconds)

1. Visit fixed URL
2. Open browser console
3. Run: new URL(location.href).searchParams.get('utm_campaign')
4. Should output: "save&win" (decoded)

Done.

Automated Fix

JavaScript One-Liner

// Fix unencoded & in UTM parameters
function fixAmpersands(url) {
    const urlObj = new URL(url);
 
    // Re-encode all parameter values
    ['utm_source', 'utm_medium', 'utm_campaign', 'utm_content', 'utm_term'].forEach(key => {
        const value = urlObj.searchParams.get(key);
        if (value) {
            urlObj.searchParams.set(key, value); // .set() with plain value auto-encodes
        }
    });
 
    return urlObj.toString();
}
 
// Usage
const broken = 'https://site.com?utm_campaign=save&win';
const fixed = fixAmpersands(broken);
console.log(fixed);
// https://site.com?utm_campaign=save%26win

Browser Console Quick Fix

// Paste this in console when on the broken URL
(function() {
    const url = new URL(window.location.href);
    const campaign = prompt('Enter correct campaign value (with &):', 'save&win');
 
    if (campaign) {
        url.searchParams.set('utm_campaign', campaign); // Auto-encodes
        window.location.href = url.toString();
    }
})();

Bulk Fix Script

// Fix multiple URLs at once
function bulkFixAmpersands(urls) {
    return urls.map(url => {
        try {
            const urlObj = new URL(url);
            const params = new URLSearchParams();
 
            // Re-encode all parameters
            for (const [key, value] of urlObj.searchParams.entries()) {
                params.set(key, value); // Properly encodes
            }
 
            urlObj.search = params.toString();
            return urlObj.toString();
        } catch (error) {
            console.error(`Failed to fix: ${"{"}{"{"}url{"}"}{"}"}}`, error);
            return url;
        }
    });
}
 
// Usage
const broken = [
    'site.com?utm_campaign=save&win',
    'site.com?utm_source=johnson&johnson',
    'site.com?utm_content=shoes&boots'
];
 
const fixed = bulkFixAmpersands(broken);
console.log(fixed);
// All & in values encoded as %26

Common Patterns & Fixes

Pattern 1: Company Name

❌ WRONG:
utm_source=procter&gamble

✅ RIGHT:
utm_source=procter%26gamble

GA4 shows: "procter&gamble"

Pattern 2: Promotional Text

❌ WRONG:
utm_campaign=buy-now&save

✅ RIGHT:
utm_campaign=buy-now%26save

GA4 shows: "buy-now&save"

Pattern 3: Product Lists

❌ WRONG:
utm_content=shoes&boots&sandals

✅ RIGHT:
utm_content=shoes%26boots%26sandals

GA4 shows: "shoes&boots&sandals"

Pattern 4: Multiple Words with &

❌ WRONG:
utm_campaign=rock&roll&music

✅ RIGHT:
utm_campaign=rock%26roll%26music

GA4 shows: "rock&roll&music"

Visual Guide: Which & to Encode

URL: ?utm_source=facebook&utm_campaign=buy&save&utm_medium=cpc
                        ↑               ↑     ↑             ↑
                     Separator      In value  Separator  Separator

Encode this one only:   ↑
Result: ?utm_source=facebook&utm_campaign=buy%26save&utm_medium=cpc

Rule: Encode & when it's part of a parameter VALUE. Leave & between parameters.

Platform-Specific Application

Google Ads

Tracking Template:
`{"{"}{"{"}lpurl{"}"}{"}"}}`?utm_campaign=buy%26save&gclid=`{"{"}{"{"}gclid{"}"}{"}"}}`
                         ↑
                    Pre-encoded in template

Facebook Ads

URL Parameters:
utm_source=facebook&utm_campaign=save%26win
                                  ↑
                             Encoded & in value

Email HTML

<a href="https://site.com?utm_campaign=buy%26save&utm_source=email">
    Click Here
</a>
 
<!-- Encoded & in HTML is preserved -->

Validation Script

function validateAmpersands(url) {
    const errors = [];
 
    try {
        const urlObj = new URL(url);
        const rawQuery = url.split('?')[1] || '';
 
        // Check each UTM parameter
        ['utm_source', 'utm_medium', 'utm_campaign', 'utm_content', 'utm_term'].forEach(key => {
            const value = urlObj.searchParams.get(key);
 
            if (value) {
                // Check if raw query has unencoded & in this parameter's value
                const paramPattern = new RegExp(`${"{"}{"{"}key{"}"}{"}"}}=([^&]*)`);
                const match = rawQuery.match(paramPattern);
 
                if (match) {
                    const rawValue = match[1];
 
                    // If contains & but not %26, it's unencoded
                    if (rawValue.includes('&') && !rawValue.includes('%26')) {
                        errors.push({
                            parameter: key,
                            issue: 'Contains unencoded &',
                            current: value,
                            fix: encodeURIComponent(value)
                        });
                    }
                }
            }
        });
 
    } catch (error) {
        errors.push({ issue: 'Invalid URL', message: error.message });
    }
 
    return {
        valid: errors.length === 0,
        errors
    };
}
 
// Usage
const url = 'site.com?utm_campaign=save&win';
const result = validateAmpersands(url);
 
if (!result.valid) {
    console.log('❌ Issues found:');
    result.errors.forEach(err => {
        console.log(`  ${err.parameter}: "${err.current}" → "${err.fix}"`);
    });
}

Alternative Solutions

Option 1: Replace with "and"

Instead of encoding, replace & with word "and":

❌ BEFORE:
utm_campaign=buy&save

✅ AFTER:
utm_campaign=buy-and-save

Easier to read, no encoding needed

Option 2: Remove Ampersand

❌ BEFORE:
utm_campaign=buy&save

✅ AFTER:
utm_campaign=buysave

Shortest option, but less readable

Option 3: Use Different Separator

❌ BEFORE:
utm_campaign=shoes&boots

✅ AFTER:
utm_campaign=shoes-boots
utm_campaign=shoes_boots
utm_campaign=shoes.boots

All valid, no encoding needed

Testing Checklist

After fixing:

✅ Visual check
   Look at URL - & in values should be %26

✅ Browser console test
   new URL('your-url').searchParams.get('utm_campaign')
   Should show decoded value with &

✅ GA4 Real-Time test
   Visit URL → Check GA4 Realtime
   Campaign should show complete value

✅ Cross-platform test
   Test on desktop & mobile
   Different browsers
   Verify consistent results

FAQ

When should I encode & and when should I leave it?

Encode & when it's PART OF a parameter value. Leave & between parameters as-is.

What if I have multiple & symbols in one value?

Encode all of them:

buy&save&win → buy%26save%26win

Does encodeURIComponent() handle this automatically?

Yes. encodeURIComponent('save&win') returns 'save%26win'.

What if my platform shows %26 literally in ads?

The platform displays encoded URL. Users will see decoded version after clicking. Test by actually clicking the link.

Conclusion

Fix unencoded & in UTM parameters in 3 steps:

1. Find & INSIDE parameter values
2. Replace with %26
3. Test in browser and GA4

❌ utm_campaign=save&win
✅ utm_campaign=save%26win

Use encodeURIComponent() to automatically encode all special characters.

Technical Reference: Ampersand Not Encoded Validation Rule