How to write an SMS that fits in 160 characters
Grasp the limit, then keep to it without sacrificing the message.
The 160-character ceiling is nothing arbitrary: it comes from the 140 usable bytes of an SMS, split into 7-bit units by the GSM-7 alphabet. As soon as a sign falls outside this alphabet — an emoji, a Cyrillic letter, an ideogram — the message switches to UCS-2 and the limit drops to 70 characters. A short, crisp text also gets through better and sends faster.
The steps
- 1
Put the essentials first
Open with the information the recipient absolutely must grasp. Even if truncated or merely glanced at in the notification, this opening will be read.
- 2
Keep an eye on the counter
The field continuously shows the remaining characters and warns you the moment a sign tips the message into the extended encoding.
- 3
Trim superfluous formulas
The SMS is a short format by nature. A greeting and a sign-off are enough; customary turns of phrase can disappear without making the message abrupt.
- 4
Reread before the countdown ends
The 60 seconds of waiting offer the ideal moment for one last cold reread, just before the message flies off.
Good to know
- •A single emoji brings the limit from 160 down to 70 characters for the whole message, not just for itself.
- •Beyond the limit, the text is split into 153-character segments, the reassembly header nibbling away the rest.
- •Write times in figures: "14h30" weighs five characters, "half past two in the afternoon" needs far more.
Common questions
Where does this figure of 160 characters come from?
An SMS carries 140 usable bytes, which gives exactly 160 characters of 7 bits in the GSM-7 alphabet.
What effect does adding an emoji have?
The whole message switches to UCS-2, where each sign takes up 16 bits: the limit then falls from 160 to 70 characters.
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