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 |
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.
