More elegant way of adding a percentage?

Question

I'm wondering if there is a more elegant way of adding a percentage. For example, if I wanted to add 12% of $a's value to $a I'm doing:

$a = 100;
$a = $a + (($a / 100) * 12);

Which gives me 112 as the new value, of course. But I can't help but feel this is a little too verbose and there must be a better way of doing the percentage addition.

I tried:

$a = $a + 12%;

But, as expected this doesn't work. Before I consider writing a function myself to make this easier, is there a pre-existing way to do this?

Answer 1

Why not $a *= 1.12;?

"Percent" comes from latin "per centum", or "per hundred". One percent is 1/100. So twelve percent is 0.12 - twelve hundredths.

Answer 2

All you need to do is:

$a *= 1.12;