# Java Program to Convert Binary Number to Decimal and vice-versa

In this program, you'll learn to convert binary number to a decimal number and vice-versa using functions in Java.

Visit this page to learn how to convert binary number to decimal.

## Example 1: Program to convert binary number to decimal

``````public class BinaryDecimal {

public static void main(String[] args) {
long num = 110110111;
int decimal = convertBinaryToDecimal(num);
System.out.printf("%d in binary = %d in decimal", num, decimal);
}

public static int convertBinaryToDecimal(long num)
{
int decimalNumber = 0, i = 0;
long remainder;
while (num != 0)
{
remainder = num % 10;
num /= 10;
decimalNumber += remainder * Math.pow(2, i);
++i;
}
return decimalNumber;
}
}``````

When you run the program, the output will be:

`110110111 in binary = 439 in decimal`

Visit this page to learn, how to convert decimal number to binary.

## Example 2: Program to convert decimal number to binary

``````public class DecimalBinary {

public static void main(String[] args) {
int num = 19;
long binary = convertDecimalToBinary(num);
System.out.printf("%d in decimal = %d in binary", num, binary);
}

public static long convertDecimalToBinary(int n)
{
long binaryNumber = 0;
int remainder, i = 1, step = 1;

while (n!=0)
{
remainder = n % 2;
System.out.printf("Step %d: %d/2, Remainder = %d, Quotient = %d\n", step++, n, remainder, n/2);
n /= 2;
binaryNumber += remainder * i;
i *= 10;
}
return binaryNumber;
}
}``````

When you run the program, the output will be:

```Step 1: 19/2, Remainder = 1, Quotient = 9
Step 2: 9/2, Remainder = 1, Quotient = 4
Step 3: 4/2, Remainder = 0, Quotient = 2
Step 4: 2/2, Remainder = 0, Quotient = 1
Step 5: 1/2, Remainder = 1, Quotient = 0
19 in decimal = 10011 in binary```