float data type precision in Java

Question

The value of the number 0.1 when stored as a single precision floating point number is 0.100000001490116119384765625 (source : https://www.h-schmidt.net/FloatConverter/IEEE754.html) but it is printed as 0.1 in Java. I think it happens because Java limits the number of decimal places in float to seven. How can I increase the number of decimal places displayed?

ideone.com/SAfXqU

shmosel
– shmosel

2019-03-11 19:10:37 +00:00
Commented Mar 11, 2019 at 19:10 — shmosel
– shmosel, Commented Mar 11, 2019 at 19:10

M.N. · Accepted Answer · 2019-03-11 19:21:41Z

6

float x = 0.1f; System.out.printf("%.17f", x); 0.10000000149011612

answered Mar 11, 2019 at 19:21

M.N.

1081 silver badge10 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Peter Lawrey · Accepted Answer · 2019-03-11 19:59:04Z

You can show all the digits with BigDecimal.

System.out.println(new BigDecimal(0.1f)); System.out.println(new BigDecimal(0.1));

This shows the precise representation. float shows up to 24 digits and double shows up to 53 digits as this is the number of bits in the mantissa.

0.100000001490116119384765625 0.1000000000000000055511151231257827021181583404541015625

This avoids needing to work out how many digits to display.

System.out.println(new BigDecimal(0.125f)); System.out.println(new BigDecimal(0.125));

prints

0.125 0.125

as this value has no representation error as it is 2^-3

@LppEdd the data type itself doesn't but it does convert to/from double correctly.

Collectives™ on Stack Overflow

float data type precision in Java

2 Answers 2

Comments

2 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Linked

Related