SMS segment calculator
An SMS segment is the billed part of a text message. One segment holds 160 GSM-7 characters, or 153 per segment in a longer text; UCS-2 texts hold 70 and 67. A 134-character reminder costs $83 a month at 10,000 texts on Twilio. One curly apostrophe makes it $249.
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Count your segments and price the month
- Segments billed per text
- 1
- Encoding
- GSM-7
- Characters
- 134 (134 septets)
- Left before the next segment
- 26
- A month in message charges
- $83
Sent as GSM-7: 160 characters fit one text, 153 per segment after that.
10,000 segments a month at Twilio's long code (10DLC) rate, 0.83c each, before number rental and carrier fees.
How SMS segments are counted
| Encoding | One text | Per segment of a longer text | Bits a character |
|---|---|---|---|
| GSM-7 | 160 | 153 | 7 |
| UCS-2 | 70 | 67 | 16 |
An SMS carries 140 bytes of user data. GSM-7 packs each character into 7 bits, so a single text holds 160 characters. UCS-2 spends 2 bytes on each character and holds 70. A longer text is split into segments, and each segment of a long text carries a 6 byte header that tells the phone how to join the parts. Plivo gives the arithmetic: 140 bytes minus 6 bytes leaves 134 bytes, and 1072 bits divided by 7 is 153 characters per segment (read September 28, 2026). A UCS-2 segment holds 67.
The SMS character limit page covers the maximum length each provider accepts.
Characters that switch a text to UCS-2
| Character | Effect |
|---|---|
| Any emoji | Moves the whole text to UCS-2 |
| Curly apostrophe or curly quotation marks (U+2018, U+2019, U+201C, U+201D) | Moves the whole text to UCS-2 |
| Long and short dashes (U+2014, U+2013) | Moves the whole text to UCS-2 |
| Accented letters outside the GSM-7 alphabet, such as á, í, ó, ú | Moves the whole text to UCS-2 |
| Euro sign, square brackets, curly brackets, caret, tilde, backslash, vertical bar, form feed | Stays GSM-7; each counts as 2 characters |
One character outside the GSM-7 alphabet, such as an emoji or a curly quotation mark, moves the whole text to UCS-2, where a segment holds 70 characters alone and 67 in a longer text (Twilio and Telnyx documentation, read September 28, 2026). One curly apostrophe in a 134-character appointment reminder changes the count from 1 segment to 3. The counter names the characters that forced the switch and offers a button that swaps curly quotes, dashes and accented letters for GSM-7 characters.
Separately, a GSM-7 extension character counts as 2 characters. Nine of them exist (3GPP TS 23.038, the standard the counter implements): the euro sign, the square and curly brackets, the caret, the tilde, the backslash, the vertical bar and the form feed. Emoji and curly quotes move a text to UCS-2; some accented letters, such as á and ó, which are outside the GSM-7 alphabet, do the same.
What segments cost at your volume
| Provider | Rate that applies | 1 segment | 2 segments | 3 segments |
|---|---|---|---|---|
| Bird (formerly MessageBird) | 0.35c, long code (10DLC) | $35 | $70 | $105 |
| Telnyx | 0.40c, long code (10DLC) | $40 | $80 | $120 |
| Bandwidth | 0.60c, long code (10DLC) | $60 | $120 | $180 |
| Clickatell | 0.75c, 0-10000 | $75.10 | $150.20 | $225.30 |
| Plivo$1,000 a month minimum (Enterprise plan) | 0.77c, long code (10DLC) | $77 | $154 | $231 |
| Sinch | 0.78c, long code (10DLC) | $78 | $156 | $234 |
| TrueDialog | 0.79c, graduated bands, blended | $79 | $158 | $237 |
| Infobip | 0.82c, one rate at any volume | $81.80 | $163.60 | $245.40 |
| Twilio | 0.83c, long code (10DLC) | $83 | $166 | $249 |
| Vonage | 0.86c, long code (10DLC) | $86 | $172 | $258 |
| CallHub | 1.90c, one rate at any volume | $190 | $380 | $570 |
| SMSGlobal | 1.90c, one rate at any volume | $190 | $380 | $570 |
| Notifyre | 2.00c, one rate at any volume | $200 | $400 | $600 |
| ClickSend | 2.08c, Growth (when you top-up from: $100) | $208 | $416 | $624 |
| BulkSMS | 3.35c, 10000 Credits bundle | $335 | $660 | $990 |
| Textmagic | 4.90c, one rate at any volume | $490 | $980 | $1,470 |
| Salesmsgentry plan, $25 a month for 500 credits; Salesmsg says credits start at 4 cents on higher plans | 5.00c, Basic plan, $25 a month for 500 credits | $500 | $1,000 | $1,500 |
| Text-Em-All | 7.00c, 10,000 to 24,999 credits bundle | $700 | $1,400 | $1,950 |
Each segment is billed as one message by the provider. Vonage states it plainly: "You are charged for each SMS part in a concatenated SMS" (read September 28, 2026). The bill for a long text is set by its segment count, so a text of 3 segments costs three times a text of 1.
At 20,000 segments a month, message charges run from $70 on Bird (formerly MessageBird) and $80 on Telnyx to $660 on BulkSMS, on each provider's published US rate (rates read September 8 and 9, 2026).
Full provider rates sit in our SMS gateway prices guide.
SMS segment questions
Does Twilio have its own segment calculator?
Twilio publishes a free Message Segment Calculator (twilio.com, read September 28, 2026). This counter prices the month on 15 providers' published US rates. See our Twilio review.
What is the maximum length of a long text?
The SMS character limit page carries the maxima for GSM-7 and UCS-2 texts, by provider and encoding.
Why did my text become 3 segments?
One character outside GSM-7, a curly apostrophe for example, moves the whole text to UCS-2, where each segment of a longer text holds 67 characters. Swap the culprit for a GSM-7 character and the count drops.
Which characters count as two?
Nine GSM-7 extension characters: the euro sign, the square and curly brackets, the caret, the tilde, the backslash, the vertical bar and the form feed. Each counts as 2 characters.
How much does a 2 segment text cost?
The provider bills each segment as one message, so a 2 segment text costs twice the per-message rate. At Twilio's long code rate of $0.0083 a segment (read September 8, 2026), that is $0.0166.