SMS pricing is based on segments, not messages. A single SMS can contain 160 characters using standard GSM encoding, but longer messages are split into multiple segments. Each segment is billed separately, so understanding character limits is crucial for managing SMS marketing costs.
GSM-7 vs Unicode Encoding
Standard SMS uses GSM-7 encoding, which supports 160 characters including the English alphabet, numbers, and basic punctuation. However, if your message contains emojis, special characters, or non-Latin letters, it switches to Unicode encoding, which only allows 70 characters per segment.
Why Multi-Segment Messages Have Fewer Characters
When a message exceeds one segment, each segment needs a "header" to tell the phone how to reassemble the message. This header takes up 7 characters in GSM (leaving 153) or 3 characters in Unicode (leaving 67).
Common Unicode Triggers
- Emojis (🎉, ❤️, 🔥)
- Smart quotes (" " instead of " ")
- Em dashes (—)
- Non-English characters (é, ñ, ü)
- Currency symbols beyond $ and € (£, ¥)
Tips to Reduce SMS Costs
- Avoid emojis in SMS (save them for email)
- Use URL shorteners to save characters
- Copy from plain text to avoid smart quotes
- Keep messages under 160 characters when possible
- Test your messages with this calculator before sending