One SMS can contain up to 160 characters (or up to 70 if special characters are used). Large content messages (concatenated SMS, multipart or segmented SMS, or “long SMS”) can be sent using multiple messages in which case each message should consist of 153 characters (67 if special characters are used).
When sending SMS messages to recipients, actual count of SMS messages may vary depending on message length. For example if message length is more than 160 characters and less than 306 characters (or more than 70 characters and less than 134 characters when special characters are used) two SMS messages will be sent to the recipient and 2 SMS credits will be deducted from your account.
When your SMS message content doesn’t fit into 1 SMS, the amount of regular messages needed will be shown in brackets inside of campaign report and activity review.