SMS Segments Explained
Message customers2 min readUpdated 2026-03-12
SMS Segments Explained
An SMS segment is the unit carriers use to transmit text messages. A single SMS can contain up to 160 GSM-7 characters or 70 Unicode characters. Longer messages are split into multiple segments and reassembled on the recipient's device.
Segment Limits
| Encoding | Single segment | Multi-segment (per segment) |
|---|---|---|
| GSM-7 (standard text) | 160 characters | 153 characters |
| Unicode (emojis, non-Latin scripts) | 70 characters | 67 characters |
Multi-segment messages use fewer characters per segment because each segment includes a 7-character header for reassembly.
How Segments Affect Cost
Each segment is billed as one message. A 320-character GSM-7 message costs the same as 3 separate messages (ceil(320/153) = 3 segments).
Examples
| Message | Encoding | Characters | Segments |
|---|---|---|---|
| "Your appointment is confirmed for tomorrow at 3 PM." | GSM-7 | 52 | 1 |
| "Hey! 👋 Welcome aboard." | Unicode | 24 | 1 |
| A 300-character plain text message | GSM-7 | 300 | 2 (153 + 147) |
| A 150-character message with one emoji | Unicode | 150 | 3 (67 + 67 + 16) |
Reducing Segment Count
- Remove emojis from long messages to stay in GSM-7 encoding.
- Enable Smart Encoding to auto-replace Unicode look-alikes.
- Keep messages under 160 characters when possible.
- Use link shorteners to reduce URL length.
Related Articles
Was this helpful?