A common task you might face when creating a web application is devising a simple, elegant method for formatting filesize. If you are using a PHP framework you most likely already have access to a function or method similar to below.

Format Filesize Code

<?php
  /**
   * Formats bytes to a human readable representation.
   * 
   * @param int $bytes
   *
   * @return string
   */
  function format_filesize($bytes) {
    $labels = array('B', 'KB', 'MB', 'GB', 'TB');
    
    foreach($labels AS $label){
      if ($bytes > 1024){
        $bytes = $bytes / 1024;
      }
      else {
        break;
      }
    }
    
    return round($bytes, 2) . $label;
  }
?>

Code Explained

<?php 
  $labels = array('B', 'KB', 'MB', 'GB', 'TB'); 
?>

You will see the simple $bytes array containing labels for each size quantifier. The order of this is important.

<?php 
  foreach($labels AS $label){
    if ($bytes > 1024){
      $bytes = $bytes / 1024;
    }
    else {
      break;
    }
  }
?>

Next we have the foreach construct allowing you to iterate or loop array members. So basically we are saying, "loop every member in $labels, and populate $label with our quantifier label". We then if $bytes can still be divided by 1024 (1024B = 1KB, 1024KB = 1MB, etc), if so then we continue to divide it, otherwise we are done working with the $bytes var and we should break; out of the loop.

<?php 
  return round($bytes, 2) . $label;
?>

The loop has now stopped executing, we can then round the remaining size with the round() function, rounding to 2 decimal places for readability. Then the proper $label was assigned during that iteration so we can simply concatenate it with the '.' character.

Results

<?php
  echo format_filesize(2000);    
?>

Will output 1.95KB

<?php 
  echo format_filesize(23423234234);   
?>

Will output 21.81GB That concludes our tiny article on how to elegantly handle filesize formatting.