Round to 2 decimal places in Java using DecimalFormat

Question

I am using DecimalFormat to round a value(in Double type) to 2 decimal places

var decimalFormat = new DecimalFormat("0.0");
decimalFormat.setRoundingMode(RoundingMode.HALF_UP);
decimalFormat.setMaximumFractionDigits(2);
return decimalFormat.format(value);

When value = 50.275 => result is 50.27 As expected, the result should be 50.28 I have tried using RoundingMode.HALF_EVEN as well but it didn't work either.

Required reading: [What Every Computer Scientist Should Know About Floating-Point Arithmetic](https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html) and [Is Floating Point Broken?](https://stackoverflow.com/q/588004/18157) — Jim Garrison, Mar 24 '23 at 21:14

score 2 · Accepted Answer · answered Mar 24 '23 at 19:20

2

50.275 cannot be represented exactly and the actual floating point value is something like 50.274999. Thus it is rounded down.

If you have 50.275 as a String, you can create a BigDecimal out of it and format that.

new BigDecimal("50.275").setScale(2, RoundingMode.HALF_UP).toPlainString();
// 50.28

answered Mar 24 '23 at 19:20

Unmitigated

76,500
11
62
80

I see, will try it and get back later. Thank you. @@ – Mr.Simple Mar 24 '23 at 19:24

Round to 2 decimal places in Java using DecimalFormat

1 Answers1