Java Numbers

Java Numbers

Java provides numeric types for whole numbers and decimal numbers.

Integer types

Whole numbers can be stored in byte, short, int, or long:

byte myByte = 100;
short myShort = 5000;
int myInt = 100000;
long myLong = 15000000000L;

Note the L at the end of the long value. Java needs it to know the number is a long.

Decimal types

float and double store numbers with decimals:

float myFloat = 5.75f;
double myDouble = 19.99d;

The f suffix marks a float, and the d suffix marks a double. The d is optional because double is the default.

Choosing a type

• Use int for everyday whole numbers.
• Use long for numbers larger than about 2 billion.
• Use double when you need decimals.
• Use float to save memory when decimals with lower precision are fine.

Scientific numbers

double also supports scientific notation with e:

double x = 1.5e3; // 1.5 * 1000 = 1500.0

TL;DR

• Whole numbers: byte, short, int, long.
• Decimals: float, double.
• long values end with L; float values end with f.