# Java.math.BigInteger.bitLength() Method

## Description

The java.math.BigInteger.bitLength() returns the number of bits in the minimal two's-complement representation of this BigInteger, excluding a sign bit. For positive BigIntegers, this is equivalent to the number of bits in the ordinary binary representation. It computes (ceil(log2(this < 0 ? -this : this+1))).

## Declaration

Following is the declaration for java.math.BigInteger.bitLength() method.

```public int bitLength()
```

NA

## Return Value

This method returns number of bits in the minimal two's-complement representation of this BigInteger, excluding a sign bit.

NA

## Example

The following example shows the usage of math.BigInteger.bitLength() method.

```package com.tutorialspoint;

import java.math.*;

public class BigIntegerDemo {

public static void main(String[] args) {

// create 2 BigInteger objects
BigInteger bi1, bi2;

// create 2 int objects
int i1, i2;

// assign values to bi1, bi2
bi1 = new BigInteger("7");
bi2 = new BigInteger("-7");

// perform bitlength operation on bi1, bi2
i1 = bi1.bitLength();
i2 = bi2.bitLength();

String str1 = "Result of bitlength operation on " + bi1 +" is " +i1;
String str2 = "Result of bitlength operation on " + bi2 +" is " +i2;

// print i1, i2 values
System.out.println( str1 );
System.out.println( str2 );
}
}
```

Let us compile and run the above program, this will produce the following result −

```Result of bitlength operation on 7 is 3
Result of bitlength operation on -7 is 3
```
java_math_biginteger.htm