SMS Parts Calculator
Billed message parts from character count and GSM or Unicode encoding.
What it does
Texting bills by parts, not by messages. A 200 character note looks like one bubble on screen but arrives as two linked segments, and carriers charge both. Knowing the boundary before sending saves split surprises.
The tool above counts billed parts from message length and encoding. Type characters and pick GSM 7-bit for plain Latin or Unicode for emoji, CJK, and many accented letters. The 200 character GSM default bills 2 parts at 153 each with 106 chars spare in the last.
The limits come from the 3GPP TS 23.040 short message standard published through ETSI: user data holds 140 octets, which packs 160 GSM septets or 70 UCS-2 characters, while concatenation headers reserve space that drops linked parts to 153 and 67. The 3GPP specification page tracks the standard across releases.
Encoding choice rules everything. GSM covers basic Latin, digits, and common symbols; anything outside, including a single emoji, forces the whole message into Unicode halves. Accented capitals and curly quotes are the classic accidental flippers.
How to use
- Count characters including spaces and line breaks.
- Pick GSM for plain Latin, Unicode for emoji or CJK.
- Read billed parts first.
- Read per part capacity to see which regime applied.
- Trim under 160 (or 70) to collapse to one part.
- Recheck after edits; one added emoji re counts everything.
Formula
- n
- Message characters counted with spaces.
- 160 / 70
- Single part capacity, GSM vs Unicode.
- 153 / 67
- Linked part capacity after header reservation.
- parts
- Billed segments after concatenation math.
140 octets of user data pack 160 seven bit septets (140 x 8 / 7) or 70 sixteen bit UCS-2 units (140 / 2). Linked messages spend header octets on segment numbering, leaving 153 septets or 67 UCS-2 units per part. Six part concatenation caps apply on some networks, which this counter flags only by count.
Worked example
Example: 200 plain GSM characters
Defaults 200 chars and GSM already filled in.
- Single check: 200 above 160, so linked math applies.
- Divide: 200 / 153 = 1.31, round up to 2 parts.
- Capacity: 2 x 153 = 306 chars total.
- Room left: 306 - 200 = 106 chars in the last part.
- Unicode twin: ceil(200/67) = 3 parts with 1 char left.
- Trim target: cut to 160 to bill a single part.
Reference table
| Characters | GSM parts | Unicode parts |
|---|---|---|
| 70 | 1 | 1 |
| 160 | 1 | 3 |
| 161 | 2 | 3 |
| 200 | 2 | 3 |
| 306 | 2 | 5 |
Limits
- Character count only; delivery, emoji rendering, and carrier caps vary.
- GSM extended symbols counting double are simplified to single here.
- Some gateways split above 6 to 8 parts or reject long chains.
- Billing follows the carrier price list, not this counter.
Common mistakes
- Assuming 160 always; linked GSM parts hold 153.
- Missing that one emoji converts the entire text to Unicode.
- Forgetting spaces and line breaks in the count.
- Quoting screen bubbles instead of billed segments to clients.
- Sending past gateway segment caps and losing the tail.
Try it yourself
Quick checks. Answers sit tucked under each question.
160 plain chars. Parts?
1 part at 160 each with 0 chars left.
161 plain chars. Parts?
2 parts at 153 each; one char tips the billing.
200 Unicode chars. Parts?
ceil(200/67) = 3 parts at 67 each with 1 char left.
Questions
Why 153 and not 160 for long texts?
Linking headers reserve 7 septets per part for segment numbering.
Why does one emoji quadruple my parts?
It forces UCS-2 encoding: 70/67 limits replace 160/153.
Do spaces count?
Yes. Every space and line break consumes capacity.
Can receivers see the split?
Modern phones rejoin linked parts into one bubble when all arrive.
Is there a maximum?
Standards allow long chains, but carriers often cap around 6 to 10 parts.
Does this include MMS?
No. Picture and group messaging bill under different rules.
Sources
- ETSI TS 123 040: Technical realization of SMS (3GPP TS 23.040)
- 3GPP Specification 23.040: Short Message Service