percentOf — GTM Variable Template for Number

VARIABLES › NUMBER

percentOf EXTENDED Number

Direct (.tpl) Apply (.tpl) Add to GTM

Calculates what percentage the first value is of the second value. Formula: (Value / Total Value) × 100.

---

When to Use This

Number Operations

Arithmetic, rounding, clamping, and mathematical transformations on numeric values.

---

Examples

Calculate percentage▶ Try

INPUT

Value: 25
Total Value: 100

OUTPUT

25

---

Live Sandbox

This is what you'll see when you open this variable in Google Tag Manager. Hover the icons for details.

percentOf

Read-Only Try Live

Value

💾 The value you want to find the percentage for.

Supported formats:
  ✓ Number
  ✓ String

Total Value

💾 The total or base value to compare against.

Supported formats:
  ✓ Number
  ✓ String

Input Setup

Input Function (optional)

⚙️ Optional pre-processing function applied to the input before internal logic (e.g., convert object to string, normalize case). Internal transformations such as case handling will still apply afterward.

Result Handling

Output Function (optional)

⚙️ Optional function to apply to the result before returning it (e.g., str => str + ' %', val => val !== undefined for boolean conversion). Useful for chaining transformations on the output.

Value number

💡 Type any text to see the result update live

🎯 Using special value — click input to type instead

Test with:

Falsy undefined null "" empty 0 false NaN

Truthy true 42 "hello" {} empty [] empty {a:1} [1,2,3]

Total Value number

🔗 Result Handling — Chain Variables

Chain apply-mode variables to the output. Each variable receives the result of the previous one.

percentOf()

+ Chain another variable

---

Related Variables

Same category: Number

→ absolute → addValues → calculateDiffRatio → ceil → clamp → classifyByThreshold → countDigits → divide → floor → max → min → multiply → parseCurrency → parseFloatValue → parseIntValue → scaleToRange → squareRoot → subtractValues → toFixed → toFixedNumber → toInteger → 🧩 WEIGHTED (Advanced) → 🧩 WEIGHTED (Predefined)

---

Under the Hood

📜 View Implementation Code

/**
* Calculates what percentage the first value is of the second value.
*
* @param {number|string} data.src - The value to find the percentage for.
* @param {number|string} data.val - The total value.
* @param {Function|string} [data.out] - Optional output handler.
*
* Direct-mode specific parameters:
* @param {Function} [data.pre] - Optional pre-processor function to transform src before calculation.
*
* @returns {number} The calculated percentage, or 0 if inputs are invalid or total is 0.
*
* @framework ggLowCodeGTMKit
*/
const Math = require('Math');
const makeNumber = require('makeNumber');

const percentOf = function(value, totalValue) {
   const val = makeNumber(value);
   const tot = makeNumber(totalValue);
   if (val !== val || tot !== tot) return 0; // Guard against NaN inputs
   if (tot === 0) return 0;
   return Math.round((val / tot) * 100);
};
const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);
// ===============================================================================
// percentOf - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const value = applyCast(data.pre, data.src);
return out(percentOf(value, data.val));
// ===============================================================================
// percentOf(...) – Apply Mode
// ===============================================================================
/*
return function(value, totalValue) {
   totalValue = data.rp1 ? totalValue : data.val;
   return out(percentOf(value, totalValue));
};
*/

🧪 View Test Scenarios (5 tests)

✅ '[example] Calculate percentage'
✅ String numbers - converts and calculates
✅ Returns 0 if total is 0
✅ Rounds to nearest integer
✅ Invalid input - returns 0