Java : round a double to four decimals

Question

I want to round a number to 4 decimals. I have done that :

roundedNumber =  (double)(Math.round(roundedNumber)*10000)/10000;

It doesn't work with a number such as : 0.20425 . I am getting the following output: 0.0

What should I do to get: 0.2042 ?

Do you need it for displaying, or do you actually need to round the number? — Kayaman, Jun 26 '15 at 07:52
You can't round doubles, but you could attempt to. In that case the parentheses are wrong: `roundedNumber = (double)(Math.round(roundedNumber*10000))/10000;` — Erwin Bolwidt, Jun 26 '15 at 07:56

score 2 · Answer 1 · answered Jun 26 '15 at 07:59

2

Use DecimalFormat

DecimalFormat decimalFormat = new DecimalFormat("#.####");
double formatedNumber =  Double.valueOf(decimalFormat.format(0.20425));

System.out.println(formatedNumber);

answered Jun 26 '15 at 07:59

codeaholicguy

1,671
1
11
18

score 1 · Accepted Answer · answered Jun 26 '15 at 07:55

1

You should mutiply before rounding:

roundedNumber = Math.round(roundedNumber*10000)/10000.0;

answered Jun 26 '15 at 07:55

Tagir Valeev

97,161
19
222
334

Java : round a double to four decimals

2 Answers2