diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 65d8be32ad..6e661228b7 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -289,7 +289,8 @@ function phpbb_gmgetdate($time = false)
 /**
 * Return formatted string for filesizes
 *
-* @param int	$value			filesize in bytes
+* @param mixed	$value			filesize in bytes
+*								(non-negative number; int, float or string)
 * @param bool	$string_only	true if language string should be returned
 * @param array	$allowed_units	only allow these units (data array indexes)
 *
@@ -301,6 +302,12 @@ function get_formatted_filesize($value, $string_only = true, $allowed_units = fa
 	global $user;
 
 	$available_units = array(
+		'tb' => array(
+			'min' 		=> 1099511627776, // pow(2, 40)
+			'index'		=> 4,
+			'si_unit'	=> 'TB',
+			'iec_unit'	=> 'TIB',
+		),
 		'gb' => array(
 			'min' 		=> 1073741824, // pow(2, 30)
 			'index'		=> 3,
diff --git a/phpBB/language/en/common.php b/phpBB/language/en/common.php
index 0184dd083b..844d5ef3ef 100644
--- a/phpBB/language/en/common.php
+++ b/phpBB/language/en/common.php
@@ -568,9 +568,11 @@ $lang = array_merge($lang, array(
 	'SUBJECT'					=> 'Subject',
 	'SUBMIT'					=> 'Submit',
 
+	'TB'				=> 'TB',
 	'TERMS_USE'			=> 'Terms of use',
 	'TEST_CONNECTION'	=> 'Test connection',
 	'THE_TEAM'			=> 'The team',
+	'TIB'				=> 'TiB',
 	'TIME'				=> 'Time',
 	
 	'TOO_LARGE'						=> 'The value you entered is too large.',
diff --git a/tests/functions/get_formatted_filesize_test.php b/tests/functions/get_formatted_filesize_test.php
new file mode 100644
index 0000000000..96ea2be132
--- /dev/null
+++ b/tests/functions/get_formatted_filesize_test.php
@@ -0,0 +1,71 @@
+<?php
+/**
+*
+* @package testing
+* @copyright (c) 2012 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+require_once dirname(__FILE__) . '/../../phpBB/includes/functions.php';
+
+class phpbb_get_formatted_filesize_test extends phpbb_test_case
+{
+	public function get_formatted_filesize_test_data()
+	{
+		return array(
+			// exact powers of 2
+			array(1, '1 BYTES'),
+			array(1024, '1 KIB'),
+			array(1048576, '1 MIB'),
+			array(1073741824, '1 GIB'),
+			array(1099511627776, '1 TIB'),
+
+			// exact powers of 10
+			array(1000, '1000 BYTES'),
+			array(1000000, '976.56 KIB'),
+			array(1000000000, '953.67 MIB'),
+			array(1000000000000, '931.32 GIB'),
+			array(100000000000000, '90.95 TIB'),
+
+			array(0, '0 BYTES'),
+			array(2, '2 BYTES'),
+
+			array(1023, '1023 BYTES'),
+			array(1025, '1 KIB'),
+			array(1048575, '1024 KIB'),
+
+			// String values
+			// exact powers of 2
+			array('1', '1 BYTES'),
+			array('1024', '1 KIB'),
+			array('1048576', '1 MIB'),
+			array('1073741824', '1 GIB'),
+			array('1099511627776', '1 TIB'),
+
+			// exact powers of 10
+			array('1000', '1000 BYTES'),
+			array('1000000', '976.56 KIB'),
+			array('1000000000', '953.67 MIB'),
+			array('1000000000000', '931.32 GIB'),
+			array('100000000000000', '90.95 TIB'),
+
+			array('0', '0 BYTES'),
+			array('2', '2 BYTES'),
+
+			array('1023', '1023 BYTES'),
+			array('1025', '1 KIB'),
+			array('1048575', '1024 KIB'),
+		);
+	}
+
+	/**
+	* @dataProvider get_formatted_filesize_test_data
+	*/
+	public function test_get_formatted_filesize($input, $expected)
+	{
+		$output = get_formatted_filesize($input);
+
+		$this->assertEquals($expected, $output);
+	}
+}