Rounding a number to exactly two decimal places for currency formatting

Question

I need to round to two decimal places for currency.

Both

Math.round(num*Math.pow(10,2))/Math.pow(10,2)

and

Math.round(num*Math.pow(10,2))/Math.pow(10,2)

work except it cuts any trailing zero's off so I get 29.9 instead of 29.90.

What is the best way around this?

Farrell

possible duplicate of Format number to always show 2 decimal places – Marje

Answer 1

You can add this to number which you want to set specific format

.toFixed(2)

Robbirobbia

toFixed(2) is not good for currency formatting since it sometimes rounds half up and sometimes half down. For example (0.615).toFixed(2) gives 0.61 (half down) while (0.625) gives 0.63 (half up). – Fronniah

For currency, Vytalyi's answer doesn't work property, to the examples that Luksaz stated. – Greybeard

@Robbirobbia answer is absolutely fine. .toFixed follows rounding principles as stated in Mathematics and as it should. If an odd number prefixes the number 5 then truncation happens else it rounds up. – Hanseatic

Yikes, (0.615).toFixed(2) is a weird wrong with returning 0.61 case. While (0.515).toFixed(2) works fine with returning the correct 0.52. – Erbium

@kaiser, it uses banker's rounding: en.wikipedia.org/wiki/Rounding#Round_half_to_even – Saltigrade

Answer 2

(Math.round(num*Math.pow(10,2))/Math.pow(10,2)).toFixed(2)

Gasconade

Actually (Math.round(0.22499999999999998*Math.pow(10,2))/Math.pow(10,2)).toFixed(2) returns 0.22 while it should be 0.23 – Finnigan

Answer 3

I am using this, seems to be ok

Math.round(x * 100)/100

Its look like shortest

Woolsack

Answer 4

It makes sense to think about it as a total amount of cents. 19.999 = 1999.9 cents, the 3rd decimal does not matter you cant pay it anyway.

This makes sense:

function convertToMoney(val){
    return (Math.floor(val*100).toFixed(0)/100).toFixed(2);
}

Vaasta