round value to 2 decimals javascript

Question

I have a small issue with the final value, i need to round to 2 decimals.

var pri='#price'+$(this).attr('id').substr(len-2);
            $.get("sale/price?output=json", { code: v },
               function(data){
                 $(pri).val(Math.round((data / 1.19),2));
            });
        });

Any help is appreciated.

Solution: $(pri).val(Math.round((data / 1.19 * 100 )) / 100);

duplicate of http://stackoverflow.com/questions/11832914/round-to-at-most-2-decimal-places-in-javascript — Mouscellaneous, May 26 '16 at 11:29

Phrogz · Answer 1 · 2014-01-31T21:40:18.497

77

If you want it visually formatted to two decimals as a string (for output) use toFixed():

var priceString = someValue.toFixed(2);

The answer by @David has two problems:

It leaves the result as a floating point number, and consequently holds the possibility of displaying a particular result with many decimal places, e.g. 134.1999999999 instead of "134.20".

If your value is an integer or rounds to one tenth, you will not see the additional decimal value:

var n = 1.099;
(Math.round( n * 100 )/100 ).toString() //-> "1.1"
n.toFixed(2)                            //-> "1.10"

var n = 3;
(Math.round( n * 100 )/100 ).toString() //-> "3"
n.toFixed(2)                            //-> "3.00"

And, as you can see above, using toFixed() is also far easier to type. ;)

edited Jan 31 '14 at 21:40

answered Feb 02 '13 at 21:45

Phrogz

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2

`toFixed(2)` rounds 1.025 to 1.02. That is not correct. If you use 1.026 it rounds correctly but not with 5 thus this rounding is wrong. – MrSmith Aug 05 '16 at 09:38
@MrSmith That's because it is not actually, exactly `1.025`. `(1.025).toFixed(20)` gives `"1.02499999999999991118"`, which is the closest JavaScript (and any language using [IEEE 754](http://en.wikipedia.org/wiki/IEEE_754-2008) 64-bit floating point numbers) can come to representing your desired `1.025`. Read more [here](http://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html) and [here](http://floating-point-gui.de/) and [here](http://floating-point-gui.de/formats/fp/) and ... – Phrogz Aug 05 '16 at 15:27

score 14 · Accepted Answer · answered Feb 02 '13 at 21:33

14

Just multiply the number by 100, round, and divide the resulting number by 100.

answered Feb 02 '13 at 21:33

David

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Do you mean $(pri).val(Math.round((data * 19 / 100),2)); ? – Dario Feb 02 '13 at 21:36
4

unless of course the number could overflow by increasing it's size. – CoderDake Feb 02 '13 at 21:36
@Dario Not exactly sure where you're getting `,2` from. – David Feb 02 '13 at 21:37
1

@TopGunCoder But we're dealing with prices here ;) – David Feb 02 '13 at 21:37
in php the round is round(value,2) and you get the last 2 decimals. – Dario Feb 02 '13 at 21:39
not sure for javascript if is the same... is because im asking for a push of help. – Dario Feb 02 '13 at 21:40
@Dario Oh, well then I don't see what the issue is here other than the fact that `2.2` should be `2`. As for Javascript, you have the use the method I described in my answer. – David Feb 02 '13 at 21:40
Resolved, $(pri).val(Math.round((data / 1.19 * 100 )) / 100); – Dario Feb 02 '13 at 21:41
by far the easiest solution! – WtFudgE Mar 30 '19 at 13:22

round value to 2 decimals javascript

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