---
title: "SMS segment"
description: "An SMS segment is one 140-octet transport unit of a text message. A message longer than one segment is split into several, and each segment is usually billed as a separate SMS."
canonical: "https://omnichannels.ai/glossary/sms-segment/"
language: "en"
updated: "2026-10-10"
publisher: "BroadNet Technologies"
brand: "OmniChannels.ai"
---

# SMS segment

Canonical: https://omnichannels.ai/glossary/sms-segment/
Language: en
Publisher: OmniChannels.ai by BroadNet Technologies

**Definition:** An SMS segment is one 140-octet transport unit of a text message. A message longer than one segment is split into several, and each segment is usually billed as a separate SMS.

The 140-octet limit comes from 3GPP TS 23.040. It holds 160 GSM-7 characters, 70 UCS-2 characters or 140 bytes of 8-bit data.

Once a message exceeds a single segment, every part carries a user data header for reassembly, leaving 153 GSM-7 or 67 UCS-2 characters per segment.

Pricing is almost always per segment, so a 161-character GSM-7 message costs two SMS, and a 71-character Arabic message costs two as well.

To control cost, keep encoding in check (avoid accidental Unicode), shorten links, and count segments rather than characters before sending a large campaign.

## Example

```
300 GSM-7 characters → 2 segments (153 + 147). 300 UCS-2 characters → 5 segments (67 × 4 + 32).
```

## Sources

- [3GPP TS 23.040 — Technical realization of the Short Message Service (SMS)](https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=747)