Question : MD5 Hash

Why is it that the last 2 bytes of the hash value are always "="?

This is how I tested it:
Dim MD5 As New System.Security.Cryptography.MD5CryptoServiceProvider
Console.WriteLine(Convert.ToBase64String(MD5.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes("test"))))

Am I doing something wrong?

Answer : MD5 Hash

Because base 64 encodes 3 bytes in 4 characters and pads to a multiple of 4 characters