SMS character limits & message length: What you should know

The character limit for SMS messages encoded in the GSM language is 160 characters, including spaces. GSM is the standard language for SMS that allows you to use Latin letters A to Z, numbers 0 to 9, and some special characters (e.g., exclamation marks).

Any SMS messages containing more than 160 characters will be split into segments of 153 characters (also known as concatenated messages). This means that a 180-character message will be sent as a 153-character message followed by a 27-character message.

If you include a single character outside of GSM, like Chinese characters, your SMS messages will be automatically converted to Unicode language (UCS). The character limit for UCS is 70—any messages that exceed this limit will be split into 67-character segments.

For example, a message containing 80 UCS-2 characters will be sent as one 67-character message followed by a 13-character message.

Although most mobile phones combine separate messages into one when they reach their destination (i.e., your customers will see one long message rather than several ones) – you will be charged for each message segment.

So, for example, if you send a GSM-encoded message with 165 characters, you will be charged twice—once for the first 153 characters and once again for the remaining 12 characters. The same goes for Unicode messages, but the limit for a single message is 70 characters in that case.

Unfortunately, you can’t circumvent the limits of a single SMS, so the best way to experience high ROI is to stay within the limit. Exceeding it will result in higher charges, questionable deliverability, and a potentially fragmented customer experience.

Staying within limits will also ensure you include only relevant content for your customers – leaving out unnecessary words, phrases, and details. This will simplify your communication and improve customer satisfaction.

Our National Language Shift is a good example of an encoding technology that allows an SMS containing 16-bit Unicode to be delivered as GSM text while deducting only five characters from the maximum SMS length. This way, you get 155 characters instead of the usual 70 characters.

If you need to send longer messages, you can explore other channels with higher limits, like RCS. It is considered the next step in the evolution of SMS, supporting rich OTT features such as a verified sender, custom branding, cards, carousels, group chats, suggested actions, and analytics. Also, RCS allows you to send messages with up to 1000 characters.

This blog was last updated in June 2024 with information about the differences in limits for GSM and Unicode messages and some frequently asked questions about SMS character limits.