Question

Is it possible to round a number where if it’s .5, just leave it, anything below .5 round down, anything above .5 round up?

For example:

• 5.0 * 1.35 = 6.75 // leave it
• 5.2 * 1.35 = 7.02 // round down to 7.00
• 5.5 * 1.35 = 7.56 // round up to 8.00

I’ve formatted with round($n,0, PHP_ROUND_HALF_UP) where $n is the product from the above calc , which leaves 6.75 but returns 7.02 for the next one. I also tried round($n,-1, PHP_ROUND_HALF_UP) which gives me the 7.00 on the second calc but then of course won’t return a 6.75 for the first, instead it returns 680.

This is a ticket markup calculation where the user enters the first number and is multiplied by the second. I actually remove the decimal because they don’t want to see it, and they want this sort of customized rounding on the result.

Answer 1

function myround($num, $prec) {
  $rhu = round($num, $prec, PHP_ROUND_HALF_UP);
  $rhd = round($num, $prec, PHP_ROUND_HALF_DOWN);

  return ($rhu + $rhd) / 2;
}

Works for any precision you like. For hundreth’s place, as in the example, $prec would need to be 2.