What Is an SMS Segment?
Understand GSM-7, Unicode and why one message can use several SMS units.
GSM-7 allows up to 160 character units for one SMS and 153 per part in longer messages. Unicode allows 70, then 67 per part. Recipient-level preview gives the most accurate estimate.
Recommended steps
- Use accurate, consent-based recipient data.
- Verify phone and placeholder mapping.
- Review previews, encoding, SMS units and cost.
- Monitor delivery and respect STOP/opt-out.