Javascript:How can I round up decimal values?

Question

I have a value like 1724.1000000000001,How can I round up values like such to 1724.11 in javascript? I need a generic function.Please help...

Answer 1

An easy way to do this is:

var num = 1724.1000000000001;
num = Math.ceil(num * 100) / 100;
alert(num); //  1724.11

How it works:

Ceil will round the value up. But you want to have 2 decimal numbers. The best way to do this is to:

1. Multiply the value with 100,
2. Round it up,
3. Divide it with 100.

Now you have an up rounded value with 2 decimals. This is what happens:

1724.1000000000001 * 100 = 172410.00000000001
round-up on 172410.00000000001 = 172411
172411 / 100 = 1724.11

Answer 2

Since the example in the questions asks for a result of 1724.11 instead of 1724.1 I would assume you don't strictly want round, but rather ceil:

var n = 1724.10000000001;
Math.ceil(n * 100) / 100; // >> 1724.11

If a simple round up to the second decimal is required us Math.round instead of Math.ceil.

Answer 3

From http://www.javascriptkit.com/javatutors/round.shtml:

var original=28.453

1) //round "original" to two decimals
var result=Math.round(original*100)/100  //returns 28.45

2) // round "original" to 1 decimal
var result=Math.round(original*10)/10  //returns 28.5

3) //round 8.111111 to 3 decimals
var result=Math.round(8.111111*1000)/1000  //returns 8.111

Answer 4

you can try toFixed to fix to 2 decimals, below is the code.

var num=1724.1999;
alert(num.toFixed(2));​

result 1724.20

Answer 5

To round a number to 2 decimals:

var num = 1724.1000000000001;
num = Math.ceil(num*100)/100;

// num == 1724.11

Or, try this:

var num = 1724.1000000000001;
function round(num, decimals){
    var d = Math.pow(10,decimals)
    return Math.ceil(num*d)/d;
}

console.log(round(num,0))
console.log(round(num,1))
console.log(round(num,2))
console.log(round(num,3))
console.log(round(num,4))
// 1725
// 1724.2
// 1724.11
// 1724.101
// 1724.1001