confused by PHP's bcmul() scale

Question

Why is this outputting 87.5 and not 87.50?

<?php

$quantity = 25;
switch ($quantity)
{
    case ($quantity <= 50):
        $price = 3.50;
        break;
    case ($quantity <= 100):
        $price = 3.00;
        break;
    default:
        break;

}
echo bcmul($price, $quantity, 2);
// 87.5

?>

Because the second decimal is a zero...it's no more preceise than 87.5. If you specified 3, and the result was 87.501, then the zero would be included. — AJ., Jun 21 '11 at 16:30
I was under the impression the scale displays whichever number you throw at it. Should I use `number_format()` to show it? — Dave Kiss, Jun 21 '11 at 16:32

score 4 · Answer 1 · answered Jun 21 '11 at 16:32

4

It is rounding the 87.50 as 87.5 would be the same. To fix, you'd need:

number_format("87.50",2);

answered Jun 21 '11 at 16:32

Francis Gilbert

3,382
2
22
27

score 2 · Accepted Answer · answered Jun 21 '11 at 16:32

2

Use number_format() instead of bcmul()

echo number_format(bcmul($price, $quantity, 2), 2, '.'); // forces to output always 2 diget after .

answered Jun 21 '11 at 16:32

powtac

40,542
28
115
170

I had this originally but decided to start using the `bcmath` functions consistently. Is there no other alternative? – Dave Kiss Jun 21 '11 at 16:34
You can use number_format() after using bcmul(). number_format() is for output formatting. – powtac Jun 21 '11 at 16:35
I put that together after seeing @Francis Gilbert's response. Thanks! – Dave Kiss Jun 21 '11 at 16:36

score 2 · Answer 3 · answered Jun 21 '11 at 16:32

2

Mathmatically 87.5 is 87.50. If you need additional number padding, you can use number_format or money_format to display the extra 0

answered Jun 21 '11 at 16:32

datasage

19,153
2
48
54

score 0 · Answer 4 · answered Dec 20 '19 at 12:48

0

for php < 7.3 use

$val = bcmul('2', '5', 2);
$val = number_format($val, 2, '.', '');

// $val = "10.00"

or use php >= 7.3 it fixed

https://www.php.net/manual/en/function.bcmul.php#refsect1-function.bcmul-notes

answered Dec 20 '19 at 12:48

Naskalin

895
9
9

confused by PHP's bcmul() scale

4 Answers4