Help Center/ Simple Message Notification/ FAQs/ What Are the Limitations on SMS Messages?
Updated on 2025-04-02 GMT+08:00
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What Are the Limitations on SMS Messages?

  • The following table describes the rules for calculating the number of characters in an SMS message.

    SMS Type

    Character Counting Rule

    Remarks

    European SMS

    SMSs in English:

    • GSM-7 characters are used for counting.
    • If an SMS contains 160 characters or less, it is counted as one SMS.

      If an SMS contains more than 160 characters, every 153 characters are counted as one SMS.
    • If an SMS contains 158 English characters, it is counted as one SMS. If an SMS contains 164 (153 + 11) characters, it is counted as two SMSs. If an SMS contains 320 (153 + 153 + 14) characters, it is counted as three SMSs.
    • For example, if an SMS template contains variable ${NUM_8} set to 123456, that variable is counted as six characters.

    SMSs in other languages:

    • Each Unicode character, such as a letter, digit, punctuation (full-width and half-width), and space, is counted as one character.
    • If an SMS contains 70 characters or less, it is counted as one SMS.

      If an SMS contains more than 70 characters, every 67 characters are counted as one SMS.

    For details, see SMS Length Calculation in Message & SMS User Guide.