SMS are billed per segment. Depending on the characters you use, the same message can count as 1, 2 or 3 SMS.
The two encodings
Standard (GSM-7)
1 SMS = up to 160 characters
Long message = 153 characters per segment
Unicode
1 SMS = up to 70 characters
Long message = 67 characters per segment
Beyond 160 characters (or 70 in Unicode), your message is split into several segments. Each segment is billed as one SMS.
A single special character changes everything
If your message contains just one non-standard character, the whole SMS switches to Unicode and the limit drops to 70 characters.
✅ Accepted (standard) characters: unaccented letters, numbers, common punctuation, é, è, à, ù, ì, ò, É, Ç, ä, ö, ü, ñ
⚠️ Characters that switch your SMS to Unicode:
emojis
ê, â, î, ô, û, ë, ï, œ, À, È
the curly apostrophe ’ (replace it with ')
quotation marks « » and “ ” (replace them with ")
the ellipsis character … (replace it with ...)
em dashes — (replace them with -)
➕ Characters that count double (without switching to Unicode): € [ ] { } \ ^ ~ |
Example
Take a 150-character message:
with no special character, it is sent as 1 SMS;
with a single "ê" or one emoji, it is sent as 3 SMS.
What about links?
Shortened links don't switch your message to Unicode. They still count toward your character total (around 20 to 30 characters).
WAX warns you
No need to count everything yourself: WAX warns you in the editor as soon as your message contains characters that switch it to Unicode or split it into several SMS. You can then fix it before sending.
below the text field, the counter shows the number of characters used and the number of SMS;
an orange box ("Sent as 2 SMS to each contact") shows which character is causing it and how many characters each part holds;
in the message preview, a badge shows the number of SMS and the Unicode label.
Our tips
Double-check anything you copy-paste from Word, Notion or Google Docs: they often add curly apostrophes and quotation marks.
Watch out for AI-written text (ChatGPT, Claude, etc.): it often contains curly apostrophes ’, quotation marks « », em dashes — and emojis, all of which switch your SMS to Unicode. Replace them before sending.
Rephrase to avoid circumflex accents (in French, "fête" can become "soirée").
Want emojis, images or buttons? Use RCS or WhatsApp, which don't have these limits.