diff --git a/wp-includes/deprecated.php b/wp-includes/deprecated.php
index bde4ea8c7b..f1e8e642e3 100644
--- a/wp-includes/deprecated.php
+++ b/wp-includes/deprecated.php
@@ -3377,9 +3377,18 @@ function gd_edit_image_support($mime_type) {
  */
 function wp_convert_bytes_to_hr( $bytes ) {
 	_deprecated_function( __FUNCTION__, '3.6', 'size_format()' );
+
 	$units = array( 0 => 'B', 1 => 'kB', 2 => 'MB', 3 => 'GB' );
 	$log   = log( $bytes, 1024 );
 	$power = (int) $log;
-	$size  = pow( 1024, $log - $power );
-	return $size . $units[$power];
+
+	if ( array_key_exists( $power, $units ) ) {
+		$size  = pow( 1024, $log - $power );
+		$unit = $units[ $power ];
+	} else {
+		$size = $bytes;
+		$unit = $units[0];
+	}
+
+	return $size . $unit;
 }