A standard text message is 160 characters long using GSM character set. If your message exceeds the limit, the message will count for 2 or more SMS (depending on the length of your message) and you will be charged accordingly. Special chars such as ~, ^, {, }, [, ], |, in the extended GSM character set will constitute two characters. Interact allows you to send longer SMS of up to 918 characters which are split into smaller SMS and later joined at the receiving end which is a mobile. In this scenario, SMS length is calculated for 153 characters as 7 characters are used to concatenate the message when it is delivered to the handset.

If your message contains unicode characters i.e., any characters outside of GSM and extended GSM character set, your standard message length will be calculated at 70 characters per message. In this scenario, SMS length is calculated for 67 characters as 3 characters are used to concatenate the message when it is delivered to the handset.

For more information on character types, check our article here.