Question

How are users charged when sending concatenated SMS?

Applies To

• Concatenated SMS
• Billing
• SMS API

Answer

When you send a message whose text is longer than the maximum number of characters per SMS, Vonage will automatically split the message for you and send multiple SMS so that your whole message will be shown as one SMS on the receiving handset.

Vonage charges per SMS we send for you (in the same way as our suppliers charge us), not per API call, so if your message is long enough to need 3 SMS to send it to the recipient we will charge you for each of these SMS individually, that is, for 3 SMS.

The maximum number of characters per single message depends on the encoding:

• 160 characters for 7-bit encoding (e.g., latin-1/9 and GSM8).
• 140 characters for 8-bit encoding (binary).
• 70 characters for 16-bit encoding (Unicode).

The maximum number of characters per concatenated message is slightly reduced due to the inclusion of concatenation headers:

• 153 characters for 7-bit encoding (e.g., latin-1/9 and GSM8).
• 134 characters for 8-bit encoding (binary).
• 67 characters for 16-bit encoding (Unicode).

Additional Information

See How is a Multipart SMS Constructed and our SMS API documentation for more information and examples about how the concatenation process works.