> For the complete documentation index, see [llms.txt](https://docs.satisfilabs.com/resource-center/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.satisfilabs.com/resource-center/marketing-engine/campaigns/messaging-campaigns/sms-regulations/sms-character-limits-and-messaging-units.md).

# SMS Character Limits & Messaging Units

SMS charges are based on *messaging units*, not just the number of messages sent. These units depend on the type of characters used in your message:

**GSM (Standard characters)**

* Messages up to 160 characters = 1 message unit.
* Messages over 160 characters are split into **153-character** segments.
* Max total: \~1,600 characters (split across multiple units).

**Unicode (Special characters like emojis, non-Latin scripts)**

* Messages up to 70 characters = 1 message unit.
* Messages over 70 characters are split into **67-character** segments.
* Max total: \~737 characters (split across multiple units).

<figure><img src="/files/EtQAgNsjzRRmdqhzalB1" alt=""><figcaption></figcaption></figure>

{% hint style="success" %}
**Note:** \
\
The number of messaging units is **clearly displayed on the UI before launching an SMS campaign**, so you can easily review expected charges before sending.
{% endhint %}