SMS Text Character Limit - 160 Characters per SMS - Tips

When sending text messages from ChiroSpring it is important to understand what character segments are and how these can affect your SMS usage. At a high-level, every 160 characters is counted as one SMS segment. These are rules set by the GSM Association (Global System for Mobile Communications), a trade body representing mobile operators worldwide.

Depending on the message content (plain text, emojis, special characters etc), ChiroSpring will use either GSM-7 or UCS-2 encoding to send the messages. Each encoding has limitations to the number of characters that can be sent. The limitations for a single segment are -

• 160 characters for GSM-7 (e.g. plain text).
• 70 characters for UCS-2 (e.g. messages with emojis, special characters or unicode)

We do not recommend using emoji as this dramatically lessens the amount of characters you can have per SMS segment (dropping from 160 to 70).

When you send a message that is longer than the maximum number of characters per segment, ChiroSpring will automatically split the message for you, add a special header (User Data Header), and send multiple SMS to carriers.

What is a User Data Header?

The User Data Header (UDH) instructs the receiving device how to reassemble the segments so that your whole message will be shown as one SMS on the receiving handset.

• Do not use emoji in your messages. These will take up 70 characters each!

• We recommend crafting your SMS messages with a buffer in them. Try and aim for a message that is 90 - 110 characters (by your best count). This should help ensure the message does not exceed 160 characters.

• Keep in mind that the replacement values can also increase/decrease the SMS size. As an example, the replacement value Patient_Name is 12 characters. If the patient's real name is longer than 12 characters, of course the SMS would contain that difference.

• If you are using a message footer, make sure to also account for this added text.

• When a message is sent there is a global footer (that cannot be edited and is required to send SMS messages) that also consumes character count. Take this message into consideration when building your SMS message. Here is the text that is sent with each SMS.

Reply STOP to opt out.

This is 18 characters of text alone. Make sure to keep this in mind as these 18 characters will count in the SMS.

You may want to use a word/character counting tool (example below) to help you craft your messages. Again, if you want to keep your messages to 1 segment or less, try and aim for 90-120 characters.

Try SMS Character Counter Tool