About SMS message length

Role: Company Administrator

The number of characters allowed in one SMS message varies depending on the character set used for the content. For example, an SMS message written in one language (such as English) might fit into one message but the same content written using a different character set (such as Chinese) might be sent as two messages and therefore incur additional charges.

A single SMS message is defined as 140 bytes using the GSM 03.38 encoding. Here are some (but not all!) examples of the maximum number of characters allowed based on particular character sets:

  • 160 characters (with each character able to be supported by the GSM-7 character set) where the message is not part of a concatenated ‘long’ message
  • 152 characters (with each character able to be supported by the GSM-7 character set) where the message is part of a concatenated ‘long’ message
  • 70 characters (with at least one multi-byte character under a UCS2, ASCII or UTF-16 character set) where the message is not part of a concatenated ‘long’ message
  • 67 characters (with at least one multi-byte character under a UCS2, ASCII or UTF-16 character set) where the message is part of a concatenated ‘long’ message.

Notes:

  • Whispir counts the characters for each SMS message according to the content delivered to each recipient. Where templates are used and dynamic values (such as @@ tags) are included in the content, it’s likely that each message sent to recipients will differ in length. (For example, using the @@web_link@@, which is only 12 characters long, might add many more characters once it's replaced by an actual URL.) This may result in:
    • A single message being split over multiple messages
    • Different recipients (of the same message) receiving a different number of SMS messages.
  • Your company will be charged for each message sent.

  • Due to reasons outside Whispir's control, total message length limits may be imposed by destination or en-route mobile carriers. If you have questions about these restrictions contact your Whispir account manager or contact the Whispir Support Team (support@whispir.com).

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