SMS Character Limit: 160, 70 and How Segments Work

A single emoji anywhere in the text is enough to move the whole message to the 70-character limit. Paste a draft into the free text message checker and it counts characters, encoding units and segments as you type.

An SMS carries 140 bytes of text. The standard alphabet for texts, called GSM-7, uses 7 bits per character, so 140 bytes fit 160 characters. GSM-7 covers English letters, digits, common punctuation and a set of accented letters such as é, è, ñ, ü and à.

When a text needs any character outside that set, the whole message is sent as Unicode (UCS-2), which uses 16 bits per character. The same 140 bytes then fit only 70 characters.

A text longer than one segment is sent as several segments that the phone joins back together, so the reader sees one message. Each segment gives up a little space to a header that tells the phone how to reassemble them. That is why the per-segment limit falls to 153 standard characters, or 67 Unicode characters.

• 161 standard characters = 2 segments.
• 307 standard characters = 3 segments (2 × 153 = 306).
• 71 characters with one emoji = 2 segments.

These are the usual culprits. Most of them sneak in when a message is written in a word processor or on a phone keyboard.

• Emoji, any of them. Most emoji also take two units each inside the 70.
• Curly quotes and apostrophes (‘ ’ “ ”). Straight quotes (‘ and “) are standard.
• Long dashes (– and —) and the ellipsis character (…). A hyphen (-) and three dots (…) are standard.
• Letters with accents outside the GSM-7 set, such as á, í, ó, ú and lowercase ç.
• Invisible characters pasted from documents, such as non-breaking or zero-width spaces.

The text message checker lists exactly which characters are forcing Unicode and offers a one-click swap for the ones that have a standard version.

A few symbols are in the GSM-7 extension table. They keep the text standard, but each one uses two characters of the limit:

{ } [ ] ~ \ | ^ €

So a 158-character text with two square brackets is 160 units and still fits one segment, but a third bracket tips it into two.

Texting providers bill per segment, not per message. A 2-segment text costs twice what a 1-segment text costs, and an emoji that pushes a 100-character reminder from 1 segment to 2 doubles its price. On a list of a few thousand contacts, that adds up quickly.

Very long texts can also be split or converted by your provider; check its limits before sending anything longer than a few segments.

1. Use straight quotes and plain dashes. Retype curly quotes, swap long dashes for a hyphen and the ellipsis character for three dots.
2. Drop the emoji in transactional texts. A reminder or confirmation reads fine without one.
3. Lead with a short business name. “Sunrise Realty:” is shorter than a full legal name and still says who is texting.
4. Use a short link on your own domain. Public shorteners such as bit.ly are filtered by carriers.
5. Keep the opt-out line short. “Reply STOP to opt out” does the job.

Then paste the draft into the text message checker: it shows the segment count, flags words carriers often filter and checks for the opt-out line. If you write texts for a team, texting from Conduyt’s CRM keeps every reply on the contact record.