<img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=1705902170274878&amp;ev=PageView&amp;noscript=1">

A concatenated SMS (Short Message Service) refers to joining multiple messages to overcome the character limit of an SMS message (160 characters). With SMS concatenation, you can send longer messages, enabling you to have meaningful interactions with customers on their mobile phones.

How does Concatenated SMS Work?

You can send a maximum of 1000 characters which will be split into 7 messages. Each SMS in a multi-part message can have up to 153 characters, in addition to the user-data headers (UDHs). UDHs are essential because they contain information about how the multi-part message should be processed such that the user receives it as a single SMS. If the mobile network does not support SMS concatenation, the message is delivered as multiple SMS messages.

Concatenated SMS

For Unicode SMS with UTF-16 encoding, each SMS can have 70 characters. Unicode messages above 70 characters will be split into multi-part, messages where each segment of the multi-part SMS can have up to 67 characters.

Concatenated SMS Character Limits

Number of SMS GSM UTF-16
1 standard SMS Max. 160 characters Max. 70 characters
2 Concatenated SMS Max. 306 characters Max. 134 characters
3 Concatenated SMS Max. 459 characters Max. 201 characters
4 Concatenated SMS Max. 612 characters Max. 268 characters
5 Concatenated SMS Max. 765 characters Max. 335 characters

Kaleyra’s robust SMS API allows you to seamlessly send long messages through concatenation. Learn more about our messaging solution here.

Schedule a Conversation

Thank you for reaching out.

Our team will be in touch with you shortly.