SMS Character Counter & Segment Calculator
A plain character count cannot predict how many SMS segments a text will use. Check the encoding, message units and estimated segments before sending.
Standard GSM-7: 160 units for one segment.
Extended characters use two units.
Calculated locally. No message is sent or stored. Segments are estimates; carrier and sender configurations can differ.
Why SMS encoding changes the number of segments
SMS messages use up to 140 bytes of payload. Standard GSM-7 messages fit 160 septets in one segment; concatenated messages reserve space for a header, leaving 153 septets per segment. The GSM extension table includes characters such as ^, {, }, \ and €; each takes two septets.
One unsupported character can switch the entire SMS to Unicode mode. A typical Unicode SMS fits 70 UTF-16 units in one segment or 67 in each concatenated segment. Emoji often use two such units. This distinction matters when a provider bills by segment, not by message.
| SMS encoding | Single segment | Multi-segment |
|---|---|---|
| GSM-7 | 160 units | 153 units each |
| Unicode (UCS-2) | 70 units | 67 units each |
For example, 161 ordinary GSM-7 characters require two concatenated segments, while 71 Unicode units require two. A curly quotation mark can change the encoding of a text that otherwise contains only English.
Estimate segments before sending bulk or transactional SMS
- Paste the exact SMS body, including links and opt-out wording.
- Check whether the encoding is GSM-7 or Unicode.
- Review the estimated segment count, especially near 70 or 160 units.
- Confirm the final segment count and any local sender restrictions with your SMS provider.
This calculator follows standard GSM-7 and Unicode segment lengths. Some carriers, national language shift tables, UDH formats and toll-free routes can differ. It is not a delivery simulator or a pricing quote. Twilio publishes the underlying SMS character and segment rules.
SMS character counter FAQ
Why did one emoji turn a one-part SMS into two parts?
An emoji is not generally available in the GSM-7 alphabet, so the message falls back to Unicode encoding. The single-part limit is reduced from 160 GSM-7 units to 70 Unicode units.
Do curly quotes and the euro sign behave the same way?
No. Smart quotation marks generally require Unicode mode, while the euro sign is part of the GSM-7 extension table and consumes two GSM septets.
Does one SMS always cost the same?
No. Providers commonly charge by segment, and prices vary by recipient country, channel and sender type. This page estimates segments only.