rounding 1000s

Hello,

I want every number to be rounded UP to the closest thousand

so 2700 should become 3000 and 2300 should also be 3000.

I am using

$num = round($num, 3);

but this will only round up OR down to the closest thousand depending on whether the number is above or below 2500.

any ideas?

I've also tried $num = round($num, +3); to no avail.

thanks

when you want to round something odd that round has trouble handling go back to the definition of rounding.

To round a number you add 0.5 * y and then round down; where y is half of the number you want to round off to.

i.e.
Round to 1, y = 0.1
Round to 10, y = 5

Okay so you want to round to 1000 this makes y = 500.

So the first step is

$x += 500

But how to round this down? The answer is with modulous arithmatic.

$x -= ($x%1000);

all done now.

Not nearly as processor efficient (yours is fantastic), but another valid method would be:

$x = ceil($x / 1000) * 1000;