SMS length calculator
Type or paste a message to see its length, how many SMS segments it will cost, and whether it encodes as GSM-7 or Unicode (UCS-2). Everything runs in your browser — nothing is sent anywhere.
GSM-7: 160 characters per single SMS (153 per segment when concatenated). Unicode: 70 per single SMS (67 per segment). Emoji and many accented or non-Latin characters force Unicode.
How SMS segments and encoding work
A single SMS can carry 160 characters when every character fits the GSM-7 alphabet — the standard Latin letters, digits and common punctuation. Longer messages are split into segments that the recipient's phone stitches back together; because each segment needs a few bytes of header, the limit drops to 153 characters per segment once a message spans more than one.
The moment a message contains a character outside GSM-7 — an emoji, a curly quote “”, or many accented and non-Latin letters — the whole message switches to Unicode (UCS-2). That cuts a single SMS to 70 characters, or 67 per segment when concatenated. One stray emoji can therefore double or triple what a message costs to send.
A handful of GSM-7 characters — ^ { } \ [ ] ~ | € — take up two character slots each, because they live in an "extension" table.
Frequently asked questions
Why did my message become Unicode?
It contains at least one character outside the GSM-7 alphabet — most often an emoji or a "smart" curly quote pasted from a word processor. Replacing those characters returns the message to GSM-7 and its 160-character limit.
How many characters is one SMS?
160 for a plain GSM-7 message. If it needs Unicode, one SMS holds 70 characters. Longer messages are split into 153-character (GSM-7) or 67-character (Unicode) segments.
Do spaces and line breaks count?
Yes. Every character counts, including spaces and line breaks. A line break is a single GSM-7 character.
Is anything I type sent to your servers?
No. The calculation happens entirely in your browser; the text never leaves your device.