How to: Convert a byte Array to an int (C# Programming Guide)

This example shows you how to use the BitConverter class to convert an array of bytes to an int and back to an array of bytes. You may have to convert from bytes to a built-in data type after you read bytes off the network, for example. In addition to the ToInt32(Byte[], Int32) method in the example, the following table lists methods in the BitConverter class that convert bytes (from an array of bytes) to other built-in types.

Type returned Method
bool ToBoolean(Byte[], Int32)
char ToChar(Byte[], Int32)
double ToDouble(Byte[], Int32)
short ToInt16(Byte[], Int32)
int ToInt32(Byte[], Int32)
long ToInt64(Byte[], Int32)
float ToSingle(Byte[], Int32)
ushort ToUInt16(Byte[], Int32)
uint ToUInt32(Byte[], Int32)
ulong ToUInt64(Byte[], Int32)

Example

This example initializes an array of bytes, reverses the array if the computer architecture is little-endian (that is, the least significant byte is stored first), and then calls the ToInt32(Byte[], Int32) method to convert four bytes in the array to an int. The second argument to ToInt32(Byte[], Int32) specifies the start index of the array of bytes.

Note

The output may differ depending on the endianess of your computer's architecture.

byte[] bytes = { 0, 0, 0, 25 };

// If the system architecture is little-endian (that is, little end first),
// reverse the byte array.
if (BitConverter.IsLittleEndian)
    Array.Reverse(bytes);

int i = BitConverter.ToInt32(bytes, 0);
Console.WriteLine("int: {0}", i);
// Output: int: 25

Example

In this example, the GetBytes(Int32) method of the BitConverter class is called to convert an int to an array of bytes.

Note

The output may differ depending on the endianess of your computer's architecture.

byte[] bytes = BitConverter.GetBytes(201805978);
Console.WriteLine("byte array: " + BitConverter.ToString(bytes));
// Output: byte array: 9A-50-07-0C

See Also

BitConverter
IsLittleEndian
Types