How Are Users Charged When Sending Concatenated SMS?
How Are Users Charged When Sending Concatenated SMS?
Applies To
-
Concatenated SMS
-
Billing
-
SMS API
Overview
When you send an SMS message that exceeds the maximum character limit for a single message, Vonage automatically splits it into multiple parts so that the recipient still receives the entire message seamlessly as one continuous text on their handset. This process is known as concatenation.
How Billing Works
Charges are applied per individual SMS sent, not per API request.
For example, if your message is long enough to require three separate SMS segments, you will be billed for three SMS messages - one for each segment sent.
This aligns with how Vonage’s network suppliers charge for message delivery.
Character Limits
The maximum number of characters you can include in a single SMS depends on the message encoding used:
| Encoding Type | Max Characters (Single SMS) | Max Characters (Concatenated SMS) |
|---|---|---|
| 7-bit (e.g., GSM8, Latin-1/9) | 160 | 153 |
| 8-bit (binary) | 140 | 134 |
| 16-bit (Unicode) | 70 | 67 |
When a message is concatenated, a portion of the message data is used to include concatenation headers, which slightly reduce the maximum available character count per segment.
Example
If you send a Unicode message that is 150 characters long:
-
Each part can hold up to 67 characters.
Your message will therefore be split into 3 segments.
You will be charged for 3 SMS messages.
