SMS (Short Message Service) is the standard protocol for sending text messages between mobile devices. It's the most widely used messaging format with near-universal device compatibility.
SMS Characteristics
160 character limit per segment
99%+ delivery rate on valid numbers
98% open rate within 3 minutes
Near-universal compatibility: Works on any mobile phone
No internet required: Uses cellular network
SMS Segmentation
Messages over 160 characters are split into segments:
1-160 characters = 1 segment
161-306 characters = 2 segments
307-459 characters = 3 segments
Unicode characters (emojis, non-Latin scripts) reduce the limit:
70 characters per segment with Unicode
153 characters per segment after first (GSM encoding)
SMS Marketing Statistics
98% open rate (vs 20% for email)
90% read within 3 minutes
45% response rate average
209% higher engagement than other channels
29% click-through rate average
SMS vs Other Channels
| Channel | Open Rate | Response Rate |
|---------|-----------|---------------|
| SMS | 98% | 45% |
| Email | 20% | 6% |
| Push | 4% | 2% |
Best Practices
Keep messages under 160 characters when possible
Avoid too many special characters
Include clear call-to-action
Test character count before sending