why the ciphertext length is not same as plaintext

Question

I am writing a encryption and decryption program with C#. This program sends the encrypted message to a unix system, and decrypts the ciphertext from the unix system. According to DES3, the plaintext length is same as encrypt-text. But I try many programs on Internet, ciphertext length is more than the plaintex. If the plaintext length is 24 bytes, then the ciphertext length is 32bytes. If the plaintext length is 48 bytes, then the ciphertext length is 64 bytes. My key is 24bytes and initial vector(IV) is 8 bytes. I don't know why. Even I try the "TextEncryption" by Gowri S Paramasivam on C# corner, same results are derived.