If you use a standard GSM 03.38 character set, single text messages are limited to 160 characters, including spaces. The maximum length of a text message is 918 characters including spaces.
The maximum length of two-part, three-part, four-part, five-part and six-part concatenated text messages is 306 (2 x 153), 459 (3 x 153), 612 (4 x 153), 765 (5 x 153) and 918 (6 x 153) characters, respectively.
Each concatenated text message is limited to 153 characters rather than 160 due to the need for user-data headers (UDHs) information. Mobile phones use UDH information to enable them to link long messages together so that they appear as single SMS messages in recipients’ phone inboxes.
The standard character set includes the Roman alphabet and the most common accented forms, certain special characters, and the Greek alphabet. It includes the following characters:
Using unicode, for such languages as Russian, Arabic, or Chinese will restrict your message to a maximum of 70 characters per SMS.
You can send longer text messages, with our system splitting them into two or at the most four separate text messages.
The maximum lengths of two-part, three-part, four-part, five-part and six-part concatenated unicode text messages are 134 (2 x 67), 201 (3 x 67), 268 (4 x 67), 335 (5 x 67) and 402 (6 x 67) characters, respectively.