Encoding:
Character Analysis
Type a message to see character analysis
Segment Breakdown
Segments will appear here
SMS Encoding Reference
| Encoding | Single SMS | Multi-part SMS | Use Case |
|---|---|---|---|
| GSM-7 | 160 characters | 153 chars/segment | English, most European languages |
| Latin-1 | 140 characters | 134 chars/segment | Extended European (accented chars) |
| UCS-2 | 70 characters | 67 chars/segment | Emoji, Chinese, Arabic, Hebrew, etc. |
GSM-7 Extended Characters
These characters are part of GSM-7 but count as 2 characters because they require an escape sequence:
^
{
}
\
[
~
]
|
€
Tips to Reduce Segment Count
- Avoid emoji — A single emoji forces UCS-2, cutting your character limit in half
- Watch extended chars — Characters like
{}[]count as 2 - Use standard quotes — Replace curly quotes (“ ”) with straight quotes (" ")
- Avoid smart punctuation — En-dash (–) and em-dash (—) force UCS-2
- Link shorteners — Use short URLs to save characters
Why Segments Matter
SMS carriers charge per segment, not per message. A 161-character GSM-7 message costs the same as a 306-character message (both are 2 segments). Understanding segments helps you:
- Optimize costs by staying within segment boundaries
- Predict delivery behavior for long messages
- Avoid unexpected charges from emoji or special characters
Multi-Part Message Overhead
When a message exceeds a single segment, each segment includes a User Data Header (UDH) that takes 6-7 bytes. This header tells the receiving device how to reassemble the parts. That's why multi-part segments hold fewer characters:
- GSM-7: 160 → 153 (7 chars for UDH)
- Latin-1: 140 → 134 (6 chars for UDH)
- UCS-2: 70 → 67 (3 chars for UDH)
SMS API for Developers
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