The Length of a standard SMS is 160 characters. WinSMS supports long SMS messages of up to 918 characters. This is equivalent to 6 concatenated messages in total.
The messages are broken up as follows: The first part will be 160 characters. The second part will be 146 characters and the remaining four parts will be 153 characters each.
Messages are concatenated in accordance with the Global System for Mobile Communications and their protocols for cellular networks using mobile devices. (This just means that it is an industry-standard your cellular network has to follow.)
Please find below SMS breakdown in more detail:
1 – 160 = 1st SMS segment.
161 - 306 = 2nd SMS segment.
307 - 459 = 3rd SMS segment.
460 - 612 = 4th SMS segment.
613 - 765 = 5th SMS segment.
766 - 918 = 6th SMS segment.