How to round numbers to the closest .45 or .95?

In PHP I want to round numbers based on the value provided.

• If the value is more than 30, I want to round numbers to the closest 4.95 or 9.95
• If the value is between 10 and 30 I want to round numbers to the closest 2.45 or 4.95 or 7.45 or 9.95
• If the value is less than 10 I want to round numbers to the closest .45 or .95
• If the value is less than 1 I want to round numbers to the closest .05 or .10

The value however cannot be 0 or below zero and always round upwards when it’s close to zero (so it doesn’t become zero but 0.05 for example).

I have this code for rounding to the closest 4.95 or 9.95:

(ROUND($number / 5, 0) * 5) - 0.05

I have this code for rounding to the closest .45 or .95:

(ROUND($number * 2, 0) / 2) - 0.05

I don’t really know how to achieve the above though. Does anyone have an idea about it?

Answer

If I understand well your problem, this solution should work :

if ($value > 30)
    $roudedValue = 5 * round($value / 5);
else if ($value >= 10)
    $roudedValue = 2.5 * round($value / 2.5);
else if ($value > 1)
    $roudedValue = 0.5 * round($value / 0.5);
else 
    $roudedValue = 0.1 * round($value / 0.1);