I need to round a float to two decimal places in Java [duplicate]

Answer 1

If you're looking for currency formatting (which you didn't specify, but it seems that is what you're looking for) try the NumberFormat class. It's very simple:

double d = 2.3d;
NumberFormat formatter = NumberFormat.getCurrencyInstance();
String output = formatter.format(d);

Which will output (depending on locale):

$2.30

Also, if currency isn't required (just the exact two decimal places) you can use this instead:

NumberFormat formatter = NumberFormat.getNumberInstance();
formatter.setMinimumFractionDigits(2);
formatter.setMaximumFractionDigits(2);
String output = formatter.format(d);

Which will output 2.30

Answer 2

1.2975118E7 is scientific notation.

1.2975118E7 = 1.2975118 * 10^7 = 12975118

Also, Math.round(f) returns an integer. You can't use it to get your desired format x.xx.

You could use String.format.

String s = String.format("%.2f", 1.2975118);
// 1.30

Answer 3

You can make use of DecimalFormat to give you the style you wish.

DecimalFormat df = new DecimalFormat("0.00E0");
double number = 1.2975118E7;
System.out.println(df.format(number));  // prints 1.30E7

Since it's in scientific notation, you won't be able to get the number any smaller than 10⁷ without losing that many orders of magnitude of accuracy.

Answer 4

Try looking at the BigDecimal Class. It is the go to class for currency and support accurate rounding.