SMS Character Limits: Why Some Messages Split Early
How the 160-character SMS limit works, why emoji reduce it to 70, how long messages are split, and how to keep campaigns within one segment.
A standard SMS can carry 160 characters. That figure comes from the GSM-7 encoding used by mobile networks, which packs basic Latin letters, digits and common punctuation into seven bits per character.
Why emoji change the limit
If a message contains even one character outside the GSM-7 set, such as an emoji, a curly quotation mark or many non-Latin letters, the whole message switches to UCS-2 (Unicode) encoding. Each character then takes 16 bits, and the limit drops to 70 characters per message.
Long messages are split into segments
Messages longer than one segment are sent as several parts and reassembled on the phone. Each part loses a few characters to header information:
| Encoding | Single message | Per segment when split |
|---|---|---|
| GSM-7 | 160 characters | 153 characters |
| UCS-2 (Unicode) | 70 characters | 67 characters |
A 200-character GSM-7 message is therefore billed as two segments.
Characters that count double
Some GSM-7 symbols, including the euro sign, square brackets, curly brackets, the backslash and the tilde, use an escape code and count as two characters.
Tips for SMS marketing
- Check length in a character counter before sending.
- Avoid emoji and smart quotes if staying in one segment matters for cost.
- Put the key message and link first in case the end is overlooked.
- Use a short link domain to save characters.
- Test on real phones from different manufacturers.
Bulk SMS platforms usually show the segment count before you send. If a 150-character message suddenly shows three segments, look for a hidden Unicode character copied from a document.
Frequently asked questions
Why do SMS messages split?
Why SMS messages split comes down to encoding. A plain GSM-7 message fits 160 characters; longer messages are broken into SMS segments of 153 characters each. One emoji switches the message to Unicode, cutting the limit to 70.
What is GSM-7 encoding?
GSM-7 encoding is the standard 7-bit character set for SMS. It covers basic Latin letters, digits and common punctuation. Characters outside it, such as emoji or curly quotes, force Unicode encoding.
How to count words on a phone?
To count words on a phone, use the word count option in your mobile document app (Google Docs on Android and iOS shows it in the menu) or paste the text into our word counter in your mobile browser. It works offline once loaded.
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