A single part SMS has a limit of 160 characters.

160 characters is a worldwide SMS standard. Each letter, number, line break, space, carriage and emoji adds to your character count. SMS messages have a limit due to the way they are transmitted. It was designed to allow a high bandwidth messaging network to run smoothly for everyone.

• 1 SMS = 160 characters
• 1 space = 1 character
• 1 line break = 1 character
• Maximum concatenated message length = 5,049 (33 x SMS parts) 

A multi-part SMS has a limit of 5,049 characters.

SMS can be joined together and delivered as one long "concatenated" message. Concatenation uses special characters to join the messages together. These invisible characters shorten each SMS part slightly. Each part of a multi part SMS is 153 characters.

With multi-part messages the cost of a message is per part. So a 4 part message will be 4x the single SMS cost.

Encoding

GSM-7

GSM is the default encoding for Latin-based languages such as English, French, and Spanish.

It supports the GSM 03.38 character set. Each character is 7 bits, thus allowing a maximum of 160 characters per SMS (1120 bits).

GSM 03.38 character set

Some 7-bit characters are not in the standard set but are part of the GSM 03.38 Extension Table. These do not convert the message to Unicode but count as 2 characters.

\         |         ^         €         {         }         [         ]         ~

The limit for SMS using special characters or languages including Emojis is 70 characters for single part and 536 for multi-part.

Characters such as emojis and Cyrillic languages will convert the message to Unicode reducing your single message character count to 70 rather than 160.

Unicode (UTF-16)

Languages that aren’t supported by GSM encoding use Unicode instead, which is commonly known as Unicode Transformation Format (UTF-16). This is due to more data being required to render the character.

Each Unicode character is 16 bits each. If you divide 1120 by 16, you get a character limit of 70 per SMS. As soon as you use one Unicode character, our platform switches to support it. The character limit per SMS will become 70 per SMS and 67 for multi-part to a 4 part maximum limit of 612 characters.

Table of character counts per SMS part

Number of SMS	GSM Count	Unicode Count
1	160	70
2	306	134
3	459	201
4	612	268
5	765	335
6	918	402
7	1,071	469
8	1,224	536

!! Be careful with character counts when using message variables

Don’t forget that custom variables, like your customer’s first name, can affect the character length of your text message. A long name can push your text message over 160 characters. You may end up sending two SMS parts instead of one. If you wish to control the message price, check that the value of your longest variable + your message does not exceed your required count.

Exceeding the character limit on a single record will only increase the price for that message not the entire campaign. So if you only have a few long names, it won't increase by much.

Need longer messages?

Customers can request an increase up to 5,049 characters (33 x SMS parts). This higher limit is available upon request and approval. Please contact us via Live Chat or submit a ticket.

 

Other things you might be interested in:

Everything you need to know about sending MMS

How to add emojis into your message