SMS message length and Unicode

Overview

SMS messages are constructed in sections, referred to as segments. Message sends are costed and charged per segment. In most geographical locations around the world, a single SMS segment represents a maximum of 160 standard GSM characters. Spaces between words are also counted as characters. When typing your message, be aware that the longer it gets, the more it will cost.

Long SMS messages

SMS messages containing more than 160 standard GSM characters are referred to as long messages. Smartphone handsets can combine or stitch multiple SMS segments into a single message. This is referred to as a concatenated message.

When segments are stitched together, seven characters are sacrificed per segment to facilitate concatenation. Therefore, the maximum character count for long messages are:

  • 2 message segments: 153+153=306 standard GSM characters
  • 3 message segments: 153+153+153=459 standard GSM characters
  • 4 message segments: 153+153+153+153=612 standard GSM characters

Standard GSM character set

The standard GSM set contains the most widely used characters in everyday language: all Latin characters (A-Z), digits (0-9), plus a few special characters such as Ö and è. For each standard GSM character typed into a message, a single character space is consumed from the SMS segment.

Extended GSM character set

In addition to standard GSM characters, certain characters from the extended GSM character set, such as € and { symbols can be used in SMS messages. The 160 segment count remains, however these characters will use additional space (x2 spaces per character).

Unicode (non-standard GSM)

Non-standard GSM characters are referred to as Unicode characters. Unicode provides a set of additional characters, including punctuation marks, mathematical symbols, technical symbols, arrows, and characters making up non-Latin alphabets such as Thai, Chinese, or Arabic script and Emojis.

While Unicode is supported in SMS messaging, be aware that its usage will affect your message length.

Introducing a single Unicode character in your message content changes the character encoding to Unicode (UCS-2) and will immediately reduce the segment character limit from 160 to 70 characters for a single message.

When messages are stitched together with Unicode characters included, three characters are sacrificed per segment. Therefore:

  • 2 message segments with Unicode: 67+67=134 characters
  • 3 message segments with Unicode: 67+67+67=201 characters
  • 4 message segments with Unicode: 67+67+67+67=268 characters

Using Emoji in your SMS messages

Emoji use is supported in SMS messaging. All Emojis are treated as Unicode characters, reducing message segments to 70 characters. Older 16-bit Emojis will count as a single character count and newer 32-bit emojis count as two characters in a message.

Unicode alert

When you include Unicode in your SMS message, you’ll get an alert to let you know there's Unicode in the message. If you meant to include Unicode, you can just ignore it, but if you didn’t, you can click on the ‘Find out more’ link. This will open a side panel which will show you what characters are Unicode. If you included Unicode by accident, such as copying and pasting an apostrophe from MS Word, you can easily delete this in the editor and replace it and the Unicode alert will disappear. You may wish to keep some Unicode–such as emojis–in your message, but remember, they may affect the length and cost of your message.

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