An SMS is broken up into segments. Each segment costs 1 SMS credit. Multiple segments can be combined to create a longer SMS.
The segment length depends on the characters used in the SMS
- GSM-7 Characters - 160
- UCS-2 (i.e. unicode) Characters - 70 | If you use a single non GSM-7 character in the SMS then this limit applies.
Once you have more than the above limit, we now need to send an ID header also meaning you are now charged 1 segment for each of the following characters:
- GSM-7 Characters - 153
- UCS-2 (i.e. unicode) Characters - 67
| Segments | GSM-7 | UCS-2 |
| 1 | 160 chars | 70 chars |
| 2 | 306 chars | 134 chars |
| 3 | 459 chars |
201 chars |
| 4 | 612 chars | 268 chars |
GSM 7 Characters (cost 1 character):
! " # $ % ' ( ) * + , - . / : ; < = > ? @ _ ¡ £ ¥ § ¿ & ¤
0 1 2 3 4 5 6 7 8 9
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
a b c d e f g h i j k l m n o p q r s t u v w x y z
Ä Å Æ Ç É Ñ Ø ø Ü ß Ö à ä å æ è é ì ñ ò ö ù ü Δ Φ Γ Λ Ω Π Ψ Σ Θ Ξ
GSM 7 Extended Characters (cost 2 characters)
| ^ € { } [ ] ~ \
Anything else, including all other languages, emojis or symbols would be sent using UCS-2.
Examples:
| Message | Type | Chars/Limit |
| Thank you for shopping | GSM-7 | 22/160 |
| Thank you for spending €10 | GSM-7 | 27/160 (€ costs 2 chars) |
| こんにちは世界 | UCS-2 | 7/70 |
| Thank you for shopping 😊 | UCS-2 (even though only 1 non GSM char) |
25/70 (😊 costs 2 chars) |
Each SMS billed is highlighted in a different colour.
Example 1: Japanese
Type: UCS-2
Total Characters: 203
Messages Billed: 4
Example 2: English
Type: GSM-7
Total Characters: 447
Messages Billed: 3
Example 3: English with Emoji
Type: UCS-2
Total Characters: 448
Messages Billed: 7 (the emoji changes the character set of the message)
You can use this tool to check the number of segments in a message:
https://twiliodeved.github.io/message-segment-calculator/