php round - Help me find my penny!

Trent_Hatred

$base = 46.4849;
$rounded = Round($base, 2);

Result = 46.48

For tax purposes, I need this to round to 46.49. How would I do this? Is "round" the proper function to be using in this case?

Thanks much,

sidney

  <?php 
$base = 46.4849; 
 $rounded = round(round($base,3),2);
echo $rounded;

// result 46.49
?>

Trent_Hatred

Hi Sidney,

I actually need the result to display 46.49 rather than 46.48. How would I roundup 46.4849 to 46.49?

sidney

my post does display 46.49

Trent_Hatred

It display 46.48 here.

🙁

sidney

strange it defiantly displaying 46.49 here

post how you used the example

Trent_Hatred

Hi Sidney,

I cut and pasted your code exactly and placed it into a new .php file, uploaded it to my server and tried it.

It displayed 46.48.

Very odd.

Trent_Hatred

Hi Sidney,

I cut and pasted your code exactly and placed it into a new .php file, uploaded it to my server and tried it.

It displayed 46.48.

Very odd.

Trent_Hatred

Sidney,

I think I found the problem:

http://bugs.php.net/bug.php?id=24142

I belive it's a discrepancy between PHP versions, which means I'll likely have to update. 😉

I'll let you know the result.

Thanks for your time,
TH

sidney

try
$rounded = round($base,3);
that should output 46.485

Trent_Hatred

Correct, it display 48.485

sidney

from the bug link

This is expected behaviour. When rounding on exact halves we round down
on evens and up on odds. If you want to always force it in one
direction on a .5 (or .05 in your case) add or substract a tiny fuzz
factor. The reason behind rounding half the values down and the other
half up is to avoid the classical banking problem where if you always
rounded down you would be stealing money from your customers, or if you
always rounded up you would end up over time losing money. By averaging
it out through evens and odds you statistically break even. If you want
to learn more, search the web for terms such as "round to even" or
"banker's rounding" and you will find that most languages actually do it
this way.

try adding 0.001 to the number before rounding

ie
$rounded=round($base+0.001,2);

Trent_Hatred

Hi Sidney,

I believe that may have done the trick. I've combined the majority of the above code into the following:

$mp2 = round($monthlyPaymentAmount * ($gst / 100) + 0.001,2);

And it is giving me proper results. A few more tests, and I may be golden. :p

Thanks for all your help,
TH

sidney

glad i was of some help

does this script do taxes as mine are due. lol