php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login
Bug #70261 Error when comparing floating point
Submitted: 2015-08-13 18:13 UTC Modified: 2015-08-13 18:59 UTC
Votes:1
Avg. Score:5.0 ± 0.0
Reproduced:1 of 1 (100.0%)
Same Version:1 (100.0%)
Same OS:1 (100.0%)
From: egdn2004 at gmail dot com Assigned:
Status: Not a bug Package: Reproducible crash
PHP Version: Irrelevant OS: All
Private report: No CVE-ID: None
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: egdn2004 at gmail dot com
New email:
PHP Version: OS:

 

 [2015-08-13 18:13 UTC] egdn2004 at gmail dot com
Description:
------------
Error when comparing floating point with two decimal places

Test script:
---------------
<?php

if (9.2 > 9.0 + 0.2) {
    echo 'WRONG';
} else {
    echo 'OK';
}

Expected result:
----------------
OK

Actual result:
--------------
WRONG

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2015-08-13 18:24 UTC] egdn2004 at gmail dot com
Test script:
---------------
<?php
$var1 = 9.22;
$var2 = 9.20;

$var_test = $var2 + 0.02;

if ($var1 > $var_test) {
    echo "WRONG\n";
} else {
    echo "OK\n";
}

if (9.22 > 9.20 + 0.02) {
    echo "WRONG";
} else {
    echo "OK";
}

Expected result:
----------------
OK
OK

Actual result:
--------------
WRONG
WRONG
 [2015-08-13 18:59 UTC] rasmus@php.net
-Status: Open +Status: Not a bug
 [2015-08-13 18:59 UTC] rasmus@php.net
Floating point values have a limited precision. Hence a value might 
not have the same string representation after any processing. That also
includes writing a floating point value in your script and directly 
printing it without any mathematical operations.

If you would like to know more about "floats" and what IEEE
754 is, read this:
http://www.floating-point-gui.de/

Thank you for your interest in PHP.

.
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved.
Last updated: Wed Jul 02 14:01:36 2025 UTC