> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wiacom.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# SMS Calculator

> Calculate how many SMS segments your message will consume and the estimated send cost before launching a campaign.

The **SMS Calculator** is a utility tool for composing SMS messages without inadvertently triggering multi-segment billing.

## How to use it

Type or paste your message text into the text area. The calculator updates in real time showing:

| Output                   | Description                                               |
| ------------------------ | --------------------------------------------------------- |
| **Character count**      | Current number of characters in the message               |
| **Characters remaining** | Characters left before the next SMS segment is created    |
| **SMS segments**         | How many individual SMS messages this content will create |
| **Estimated cost**       | Total cost at your account's current per-SMS rate         |

## SMS segment rules

A standard SMS is 160 characters using the GSM-7 character set. If your message contains any character outside the GSM-7 set (for example, certain accented characters, emoji, or smart quotes), the encoding switches to Unicode (UCS-2) and the per-segment limit drops to 70 characters.

For multi-segment messages, each segment has a slightly lower character limit because some characters are reserved for the concatenation header:

| Encoding        | Single SMS     | Each segment in a multi-SMS |
| --------------- | -------------- | --------------------------- |
| GSM-7           | 160 characters | 153 characters              |
| Unicode (UCS-2) | 70 characters  | 67 characters               |

<Warning>
  A message that is 161 characters in GSM-7 encoding will be billed as **2 SMS messages** for every recipient. Always check the segment count before scheduling a bulk campaign.
</Warning>

Use the SMS Calculator to finalise your message content before pasting it into the [Advanced Campaigns](/client-reference/campaigns/advanced-campaigns) or [Live Campaigns](/client-reference/campaigns/live-campaigns) composer.