If a message contains one or more non-GSM characters, the entire message is automatically converted to Unicode in order to successfully deliver the message. One message part equals 160 GSM characters or 70 Unicode characters, which means that using non-GSM characters in your messages could result in additional and inflated costs per message.

To check whether your messages contain non-GSM characters, navigate to Tools -> Non-GSM Character Checker and enter the text that you want to send. Any non-GSM characters will be highlighted in red. Remove non-GSM characters to ensure that you only pay for one message part.