Round to at most 2 decimal places (only if necessa

Question

I'd like to round at most 2 decimal places, but only if necessary.

Input:

10
1.7777777
9.1

Output:

10
1.78
9.1

How can I do this in JavaScript?

Answer 1

One can use .toFixed(NumberOfDecimalPlaces).

var str = 10.234.toFixed(2); // => '10.23'
var number = Number(str); // => 10.23

Answer 2

One way to achieve such a rounding only if necessary is to use Number.prototype.toLocaleString():

myNumber.toLocaleString('en', {maximumFractionDigits:2, useGrouping:false})

This will provide exactly the output you expect, but as strings. You can still convert those back to numbers if that's not the data type you expect.

Answer 3

This may help you:

var result = (Math.round(input*100)/100);

for more information, you can have a look at this link

Math.round(num) vs num.toFixed(0) and browser inconsistencies

Answer 4

None of the answers found here is correct. @stinkycheeseman asked to round up, you all rounded the number.

To round up, use this:

Math.ceil(num * 100)/100;

Answer 5

2017
Just use native code .toFixed()

number = 1.2345;
number.toFixed(2) // "1.23"

If you need to be strict and add digits just if needed it can use replace

number = 1; // "1"
number.toFixed(5).replace(/\.?0*$/g,'');

Answer 6

Here is a simple way to do it:

Math.round(value * 100) / 100

You might want to go ahead and make a separate function to do it for you though:

function roundToTwo(value) {
    return(Math.round(value * 100) / 100);
}

Then you would simply pass in the value.

You could enhance it to round to any arbitrary number of decimals by adding a second parameter.

function myRound(value, places) {
    var multiplier = Math.pow(10, places);

    return (Math.round(value * multiplier) / multiplier);
}