No, there's an extra 20. SMS messages are 140 bytes: 160 7-bit characters, 140 8-bit characters, or 70 UCS-2 16-bit characters. Twitter used 160-character tex

No, there's an extra 20. SMS messages are 140 bytes: 160 7-bit characters, 140 8-bit characters, or 70 UCS-2 16-bit characters. Twitter used 160-character text messages, where 140 characters were the tweet itself, and the rest was the username.