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SMS Limits and Guidelines
Get to know the limits that apply to sending SMS messages in MobileStudio.
SMS Message Length Limits
The maximum number of characters in an SMS message depends on how the characters are encoded. All unaccented Latin characters are part of the encoding system known as the GSM 03.38 character set. A single message can contain up to 160 characters, as long as it only contains characters in the GSM 03.38 character set. If a message contains one or more characters that aren’t in the GSM 03.38 character set, it’s encoded using a different encoding system called UCS-2. A message that’s encoded using UCS-2 can contain up to 70 characters.
If a message contains more than 160 GSM 03.38 or 70 UCS-2 characters, the message is split into separate message parts. These message parts can be joined on the recipient’s device so that they appear as a single message. The process of joining messages is called concatenation. Support for concatenation varies depending on the recipient’s country, carrier, and mobile device.
| Resource | Maximum | Details |
|---|---|---|
| Maximum number of characters in a single message |
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| Maximum number of characters per message part for a multi-part message |
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Each multi-part message contains hidden information that identifies the message that comes before it in order. This extra information reduces the number of characters that are allowed in a single message part. |
| Maximum number of message parts in a multi-part message | 10 message parts | Different carriers around the world have different limits. Salesforce doesn’t strictly enforce this limit. We provide this number as a guideline for obtaining the best results across different countries, carriers, and devices. |
If you copy and paste text from a word processor into your SMS messages, make sure that it hasn’t replaced characters with similar-looking characters. For example, word processors often replace straight quotes (") with curly quotes (“ and ”). Although these characters look similar, they’re not the same. Straight quotes are part of the GSM 03.38 character set, but curly quotes aren’t.
If you include curly quotes in a message that otherwise only contains GSM 03.38 characters, the entire message is sent using UCS-2 encoding. This change in encoding reduces the maximum length of the message by more than half.
