SMS character limits and credit usage guide

Learn how message length and special characters affect SMS segments and credit usage in Caspen.

Overview

Caspen uses standard SMS rules, which determine how long a message can be before it is split into segments. This is useful to know when writing appointment or class notifications, since longer messages can use more SMS credits.

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How SMS segments work

Standard GSM characters:

• 1 segment = 160 characters.

• Long messages use 153 characters per segment.

With emojis or special characters:

• 1 segment = 70 characters.

• Long messages use 67 characters per segment.

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What counts as standard GSM

• Letters, numbers, spaces, and common punctuation (A–Z, a–z, 0–9, . , ! ? ' " : ; ( ) / @ #).

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Special characters

Special characters include:

• Curly quotes “ ” and ‘ ’

• Long dashes

• Many accented letters (for example, é or ü)

• Symbols such as { } [ ] ^ \ |

• Emojis

Using emojis or special characters reduces how many characters fit in one SMS, which may increase the number of segments (and credits) used.

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Cost

You use 1 SMS credit per outbound segment.

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Tips to reduce SMS costs

• Keep SMS short and clear.

• Use standard GSM characters.

• Limit emojis and special characters where possible, as they can increase cost.

• If you’re curious about credits, try an online SMS segment calculator to estimate usage.