Part-1: Best Practices for SMS A2P Message Encoding 

Do you find that your carefully crafted SMS messages are getting split into two or more messages? Split messages are not only frustrating but costly. Mobile Network Operators (MNOs) and other messaging partners transmit the second and even third messages separately and charge for the additional texts resulting in higher fees. Let’s help you uncover the hidden reasons behind split messages and how to avoid them to level up your messaging game and save money.  

The character limit for SMS messages is 160 including letters, numbers, punctuation marks, and spacing when encoded in GSM-7, a character encoding standard. Characters outside of the GSM-7 standard – including emojis – use more data. Some characters consume twice as much data leaving you with fewer available characters to include in your message. This is often the reason messages exceed the bytes of data allowed. As a result, the message gets split. Consequently, UCS-2 character encoding is used for SMS messages. Here are some examples of characters that consume more data:  

If the message exceeds the 160 character limit or includes characters not supported by the GSM-7 character set, it gets split into two or more messages.  

MNOs and messaging partners view messages based on character count and characters supported by the GSM-7 standard. Even though you may see one message when you’re drafting it in the message content box, it gets split in two if the total bytes consumed exceeds the number of bytes 160 characters represent in the GSM-7 standard.  

Here’s what you can do to avoid using common characters that are heavier on bytes. 

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Encoding: UCS-2
SMS count: 3
Characters in message: 158
Characters in SMS: 67

Encoding: GSM-7
SMS count: 1
Characters in message: 158
Characters in SMS: 160  

To convert this to a single message, we shortened the dash to a hyphen and typed a plain apostrophe directly in the message content box. In this format, it will transmit as one message.

Here is another tip – not all characters used in Microsoft applications are part of the GSM-7 standard. As a best practice, avoid drafting a message in Word, for example, and then pasting it into your message content box. If you prefer using Microsoft apps to draft messages, paste your messages into a plain text editor first. This will enable you to spot non-GSM-7 characters and replace or remove any formatting. Once the formatting is removed, paste it into your message content box.

If 160 characters is too limiting, SMS may not be the best messaging channel for your business. Explore other messaging channels to discover which are the best for your business.

Keep these practical tips in mind to create a more seamless A2P Messaging experience for you and your customers.