Understanding SMS Message Segments
When sending SMS messages, the number of characters that fit in one segment depends on how your message is encoded. The key point to remember is that the character limit per segment changes based on whether your message uses standard text or includes emojis and special characters.
Segment Limits by Message Type
Standard Text (GSM-7)
Messages with standard characters only (no emojis or special characters):
Unicode Messages (UCS-2)
Messages with emojis or non-GSM characters (e.g., emojis, accented characters, non-Latin scripts):
Examples
Example 1: Standard Text
Message: "Sale today only! Reply YES to claim."
Example 2: Message with Emoji
Message: "Sale today only! 🎉 Reply YES to claim."
Example 3: Mixed Content
Message: "👋 Hi Sarah, your appointment is tomorrow at 3:30pm. Reply YES to confirm."
Test Your Messages
You can test your own message content (with or without emojis) to see the exact encoding and number of segments before sending:
SMS Segment Calculator
Simply paste your message content into the calculator to see how many segments it will use.
Test Your Messages using an API
If you’d rather perform test using our API, you can do so with the below API, just replace the text parameter with your text:
curl --location 'https://api.atomtel.com/api/atomic/sms/calculator' \
--header 'Content-Type: application/json' \
--data '{
"text": "👋 Hi Sarah, your appointment is tomorrow at 3:30pm. Reply YES to confirm."
}'