What is Long SMS?

A text message that exceeds 160 characters and is automatically split into multiple linked segments that reassemble into a single continuous message on the recipient's device.

Standard SMS has a character limit of 160 characters (GSM-7 encoding) or 70 characters (Unicode). When a message exceeds these limits, it is automatically split into multiple SMS segments. Each segment includes a User Data Header (UDH) that contains a reference number and sequence information, allowing the recipient's device to reassemble the segments in the correct order. For GSM-7 messages, each segment in a long SMS can carry 153 characters (7 reserved for UDH), and for Unicode, 67 characters per segment. Long SMS is billed per segment, so a 320-character GSM-7 message counts as 2 SMS units. BhashSMS handles concatenation automatically, and businesses can preview segment counts in the platform before sending.

Frequently Asked Questions

Compliance

How is a long SMS billed—as one message or multiple?

Long SMS is billed per segment. A 320-character GSM-7 message splits into 2 segments and is charged as 2 SMS. Always check the segment count in your platform before sending bulk long SMS to manage costs accurately.

Speed

What happens if segments of a long SMS arrive out of order?

The UDH (User Data Header) in each segment contains sequence information that the recipient's device uses to reassemble segments in the correct order, regardless of which segment arrives first. The final display is always correct.

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Related Terms

Promotional SMS OTP DND Bulk SMS Sender ID SMS Gateway Priority Route TRAI 2FA

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