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I am trying to do this but is all I have found is rounding to the nearest whole number. I was wondering if there was a way to do this with math.round or if there is a different solution. Thanks!

Tech Hax
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  • please add some more use cases and what you have tried. – Nina Scholz Jul 16 '18 at 08:14
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    Possible duplicate of [Round to at most 2 decimal places (only if necessary)](https://stackoverflow.com/questions/11832914/round-to-at-most-2-decimal-places-only-if-necessary) – Rawling Jul 16 '18 at 08:15
  • I have looked around quite a bit and not found anything, the link that you sent dosn't work in my case because i want it rounded to the tenth, not 100th. – Tech Hax Jul 16 '18 at 08:20
  • @TechHax _“because I want it rounded to the tenth, not 100th”_ — but hopefully you understand the solutions given in the answers and can easily adjust them, right? We don’t need a new question for every possible rounding. – Sebastian Simon Jul 16 '18 at 08:26
  • Possible duplicate of [How do you round to 1 decimal place in Javascript?](https://stackoverflow.com/questions/7342957/how-do-you-round-to-1-decimal-place-in-javascript) – Sebastian Simon Jul 16 '18 at 08:28

2 Answers2

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Method 1: The quick way is to use toFixed() method like this:

var num = 2.12;
var round = num.toFixed(1); // will out put 2.1 of type String

One thing to note here is that it would round 2.12 to 2.1 and 2.15 to 2.2

Method 2: On the other hand you can use Math.round with this trick:

var num = 2.15;
Math.round(num * 10) / 10; // would out put 2.2

It would round to the upper bound.

So, choose whichever you like.

Also if you use a modern version of JS ie. ES then using const and let instead for variable declaration might be a better approach.

NOTE: remember that .toFixed() returns a string. If you want a number, use the Math.round() approach. Thanks for the reminder @pandubear

tmw
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    _“One thing to note here that it would round `2.15` to `2.1` and `2.15` to `2.2`.”_ — only at most one of these is true. You probably also want to explain why this is; there exist [different rounding methods](https://stackoverflow.com/q/977796/4642212). – Sebastian Simon Jul 16 '18 at 08:30
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    Worth warning that .toFixed() returns a string. If you want a number, use the Math.round() approach. – Pandu Jun 14 '21 at 17:41
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Math.round(X);           // round X to an integer
Math.round(10*X)/10;     // round X to tenths
Math.round(100*X)/100;   // round X to hundredths
Math.round(1000*X)/1000; // round X to thousandths
Nelson_Frank
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  • Hope It will solve issue but please add explanation of your code with it so user will get perfect understanding which he/she really wants. – Jaimil Patel Jun 01 '20 at 04:59