You can send up to 160 GSM characters (a standard developed to describe the protocols for 2G digital or cellular networks used by mobile phones) or if you need to send characters outside the GSM charset, 70 UCS-2 characters in a single SMS message. 

If the body can't fit into a single message, it will be automatically split into multiple messages. For GSM messages, these parts will contain up to 153 characters and for UCS-2 encoding, these messages will contain up to 67 characters. The maximum number of parts that can be generated is 8.