It is easy to calculate Ielts listening and reading band score compared to speaking and writing band score. In speaking and writing score evaluation is done on basis of 4 criteria.
Before calculating band score you need to understand test pattern. Listening test is divided in to 4 parts, in each part you get 10 questions. Each question in test contains 1 mark so maximum you can score 40 and minimum 0 mark. There is no negative marking system in IELTS listening test.
After getting score you need to convert your score in to band score and it is very easy. If you need dedicated band score calculate try out application UtterMost : IELTS Preparation app or else use this simple table to convert your score in to band