Java - format double value as dollar amount

Question

I need to format the double \"amt\" as a dollar amount println(\"$\" + dollars + \".\" + cents) such that there are two digits after the decimal.

What is the best wa

Answer 1

Use NumberFormat.getCurrencyInstance():

double amt = 123.456;    

NumberFormat formatter = NumberFormat.getCurrencyInstance();
System.out.println(formatter.format(amt));

Output:

$123.46

Answer 2

You can use a DecimalFormat

DecimalFormat df = new DecimalFormat("0.00");
System.out.println(df.format(amt));

That will give you a print out with always 2dp.

But really, you should be using BigDecimal for money, because of floating point issues

Answer 3

Use DecimalFormat to print a decimal value in desired format e.g.

DecimalFormat dFormat = new DecimalFormat("#.00");
System.out.println("$" + dFormat.format(amt));

If you wish to display $ amount in US number format than try:

DecimalFormat dFormat = new DecimalFormat("####,###,###.00");
System.out.println("$" + dFormat.format(amt));

Using .00, it always prints two decimal points irrespective of their presence. If you want to print decimal only when they are present then use .## in the format string.

Answer 4

You can use printf for a one liner

System.out.printf("The original balance is $%.2f.%n", cardBalance);

This will always print two decimal places, rounding as required.

Answer 5

Use BigDecimal instead of double for currency types. In Java Puzzlers book we see:

System.out.println(2.00 - 1.10);

and you can see it will not be 0.9.

String.format() has patterns for formatting numbers.