bcmath - Decimal multiplication in php -

i having problem multiplication of 2 decimals 30.63 , 0.15. calculator says should result in 4.60.

$commission = bcmul(30.63, 0.15,2); 

result 4.59.

from had read bcmul meant work decimal numbers?

many thanks,

from the documentation $scale parameter bcmul:

this optional parameter used set number of digits after decimal place in result.

this means number rounded down (or negative number) when it's used, e.g.

> echo bcmul(0.99, 1, 1); 0.9 

for values, 30.63 * 0.15 equal 4.5945. supplying $scale value of 2 means 4.59, you've reported.

i'm not sure why you're expecting 4.60, unless you're expecting result rounded up.