php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #43867 Invalid round() function output
Submitted: 2008-01-16 15:13 UTC Modified: 2008-01-26 00:58 UTC
Votes:3
Avg. Score:4.7 ± 0.5
Reproduced:1 of 1 (100.0%)
Same Version:1 (100.0%)
Same OS:0 (0.0%)
From: pjotrik at post dot cz Assigned:
Status: Not a bug Package: *Math Functions
PHP Version: 5.2.5 OS: Windows XP SP2
Private report: No CVE-ID: None
View Developer Edit
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: pjotrik at post dot cz
New email:
PHP Version: OS:

 

 [2008-01-16 15:13 UTC] pjotrik at post dot cz 
Description:
------------
When I try to round a number like X.YZ5 with precision 2, I get X.YZ, but Z number should be incremented to Z+1

Reproduce code:
---------------
$a=round(2.225,2);

Expected result:
----------------
$a=2.23

Actual result:
--------------
$a=2.22

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2008-01-16 15:46 UTC] pjotrik at post dot cz 
Sorry, I have a better example:

echo (4.3*((100-25)/100));
    ----> result: 3.225

echo round(4.3*((100-25)/100),2);
    ----> result: 3.22

echo round(3.225,2);
    ----> result: 3.23
 [2008-01-26 00:58 UTC] jani@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://docs.sun.com/source/806-3568/ncg_goldberg.html
 
Thank you for your interest in PHP.
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved. 		Last updated: Tue Nov 04 02:00:01 2025 UTC