## How can I convert a long to int in Java?

### Question

How can I convert a long to int in Java?

2012/08/17
1
325
8/17/2012 1:39:07 PM

``````Long x = 100L;
int y = x.intValue();
``````

2014/07/15

For small values, casting is enough:

``````long l = 42;
int i = (int) l;
``````

However, a `long` can hold more information than an `int`, so it's not possible to perfectly convert from `long` to `int`, in the general case. If the `long` holds a number less than or equal to `Integer.MAX_VALUE` you can convert it by casting without losing any information.

For example, the following sample code:

``````System.out.println( "largest long is " + Long.MAX_VALUE );
System.out.println( "largest int is " + Integer.MAX_VALUE );

long x = (long)Integer.MAX_VALUE;
x++;
System.out.println("long x=" + x);

int y = (int) x;
System.out.println("int y=" + y);
``````

produces the following output on my machine:

``````largest long is 9223372036854775807
largest int is 2147483647
long x=2147483648
int y=-2147483648
``````

Notice the negative sign on `y`. Because `x` held a value one larger than `Integer.MAX_VALUE`, `int y` was unable to hold it. In this case, it wrapped around to the negative numbers.

If you wanted to handle this case yourself, you might do something like:

``````if ( x > (long)Integer.MAX_VALUE ) {
// x is too big to convert, throw an exception or something useful
}
else {
y = (int)x;
}
``````

All of this assumes positive numbers. For negative numbers, use `MIN_VALUE` instead of `MAX_VALUE`.

2020/08/13

Since Java 8 you can use: Math.toIntExact(long value)

Returns the value of the long argument; throwing an exception if the value overflows an int.

Source code of `Math.toIntExact` in JDK 8:

``````public static int toIntExact(long value) {
if ((int)value != value) {
throw new ArithmeticException("integer overflow");
}
return (int)value;
}
``````
2016/04/27

If using Guava library, there are methods `Ints.checkedCast(long)` and `Ints.saturatedCast(long)` for converting `long` to `int`.

2016/09/13

``````long x = 3;
int y = (int) x;
``````

but that assumes that the `long` can be represented as an `int`, you do know the difference between the two?

2010/12/04