How to write an SMS in 160 characters
Understand the limit, then work within it without losing meaning.
The 160-character limit is not arbitrary: it follows from the 140 bytes of payload in an SMS, split into 7-bit units by the GSM-7 alphabet. As soon as one character falls outside that alphabet — an emoji, a Cyrillic letter, an ideogram — the message switches to UCS-2 and the limit drops to 70 characters.
The steps
- 1
Put the essential part first
Start with what the recipient absolutely must know. If the message is truncated or merely glanced at, that part still gets read.
- 2
Watch the live counter
The field constantly shows how many characters are left and flags the moment a character tips the message into extended encoding.
- 3
Cut the unnecessary courtesies
An SMS is a brief format by nature. A greeting and a sign-off are enough; stock phrases can go without the message reading as curt.
- 4
Reread before the countdown ends
The 60-second wait is the ideal moment for one last, cool-headed read before the message goes out.
Worth knowing
- •One emoji cuts the limit from 160 to 70 characters for the whole message, not just for itself.
- •A longer message is split into 153-character segments, the reassembly header taking up the difference.
- •Write numbers as digits rather than words: "2:30pm" costs six characters, "half past two" thirteen.
Frequently asked questions
Why 160 characters and not some other number?+
Because an SMS carries 140 bytes of payload, which gives exactly 160 seven-bit characters in the GSM-7 alphabet.
What happens if I use an emoji?+
The whole message switches to UCS-2 encoding, where each character takes 16 bits, so the limit drops from 160 to 70 characters.
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