Rounding numbers to 2 digits after comma

UPDATE: Keep in mind, at the time the answer was initially written in 2010, the bellow function toFixed() worked slightly different. toFixed() seems to do some rounding now, but not in the strictly mathematical manner. So be careful with it. Do your tests... The method described bellow will do rounding well, as mathematician would expect.

• toFixed() - method converts a number into a string, keeping a specified number of decimals. It does not actually rounds up a number, it truncates the number.
• Math.round(n) - rounds a number to the nearest integer. Thus turning:

0.5 -> 1; 0.05 -> 0

so if you want to round, say number 0.55555, only to the second decimal place; you can do the following(this is step-by-step concept):

• 0.55555 * 100 = 55.555
• Math.Round(55.555) -> 56.000
• 56.000 / 100 = 0.56000
• (0.56000).toFixed(2) -> 0.56

and this is the code:

(Math.round(number * 100)/100).toFixed(2);

EDIT 2:

Use the Number object's toFixed method like this:

var num = Number(0.005) // The Number() only visualizes the type and is not needed
var roundedString = num.toFixed(2);
var rounded = Number(roundedString); // toFixed() returns a string (often suitable for printing already)

It rounds 42.0054321 to 42.01

It rounds 0.005 to 0.01

It rounds -0.005 to -0.01 (So the absolute value increases on rounding at .5 border)

jsFiddle example