PHP: Calculate the percentage of a number.

This is a short guide on how to calculate the percentage of a given number in PHP. For example: What is 25% of 100? Or what is 10% of 728?

In this code snippet, I have put each calculation on its own separate line, just to make the math a little clearer:

<?php

//My number is 928.
$myNumber = 928;

//I want to get 25% of 928.
$percentToGet = 25;

//Convert our percentage value into a decimal.
$percentInDecimal = $percentToGet / 100;

//Get the result.
$percent = $percentInDecimal * $myNumber;

//Print it out - Result is 232.
echo $percent;

A quick summary of what we did:

  1. We used the number 928 for example purposes.
  2. We specified that we wanted to get 25% of 928.
  3. We converted our percentage value into a decimal number by dividing it by 100. This turns 25 into 0.25.
  4. We then multiplied 0.25 by 928.
  5. The end result is 232, which means that 25% of 928 is 232.

Function.

If you’re looking for a simple PHP function to use in your projects, then you can use the following:

/**
 * A simple PHP function that calculates the percentage of a given number.
 * 
 * @param int $number The number you want a percentage of.
 * @param int $percent The percentage that you want to calculate.
 * @return int The final result.
 */
function getPercentOfNumber($number, $percent){
    return ($percent / 100) * $number;
}

echo getPercentOfNumber(928, 25);

I’m using the same example figures, just to demonstrate that the result is the same. As you can see, the¬†calculation can be done with one simple line of code.

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