Special Character Considerations for SMS Messaging

Michelle_Peruskie — Wed, 23 Jul 2025 09:51:15 GMT

Special characters in SMS messages are encoded automatically, but adding them can sometimes make for longer character length in messaging. You can send up to 160 characters in a single SMS if they fall under the GSM-7 (7-bit characters) alphabet.

In this body example, the á in Chávez and ¡ in ¡SALUD!are not GSM-7 characters:

{ “body” : “To celebrate the start of apple picking season: buy one basket, get one free at our César Chávez, Texas location this weekend. ¡SALUD!” }

So, the message will be sent using UCS-2 encoding. UCS-2 encoding takes 2 bytes per character. That means that the new maximum becomes 70 characters. Each character in the whole message will sent in Unicode.

This will result in an increase in the number of messages. Although the user will not see how many messages are sent (because they will be reassembled as one message on their end - up to 2,000 characters) it can affect the cost to you. Long messages will also take up a few extra characters per message to account for the header on each message.

This is all part of the standard messaging protocols for SMS transmission, but if you would like more help in determining the number of message segments and the cost impact, reach out to your Sinch Account Manager.

Visit the Sinch SMS product page to learn more about our SMS product.

article Special Character Considerations for SMS Messaging in SMS

Special Character Considerations for SMS Messaging