Short Message Service:Limitations

Encoding method

SMS character limit

GSM-7 Encoding

When you send an SMS message containing more than 160 characters, the message is split into smaller messages for transmission. These smaller messages are known as "segments" and consist of up to 153 characters each. A signature with square brackets is included with each segment to ensure proper reassembly by the device of the recipient, reducing the effective character limit per segment to 153.

Standard characters are counted as one character, while extended characters are counted as two characters. Extended characters include: | ^ € { } [ ] ~ \.

Example: If a message contains 350 characters, it is split into three messages. The first two messages contain 153 characters each and the last message contains 44 characters.

UCS-2 Encoding

SMS messages are typically encoded using the GSM-7 character set, which supports standard Latin characters and a limited set of special characters. However, if you include non-GSM-7 characters, such as Chinese script or emoji, in your SMS messages, they will need to be sent using the UCS-2 encoding.

Messages that contain one or more UCS-2 characters can contain up to 70 characters in a single, non-segmented message. If the message exceeds 70 characters, it will be split into multiple segments, with each segment containing up to 67 characters.

Example: If a message contains 150 characters, it is split into three messages. The first two messages contain 67 characters each and the last message contains 16 characters.