How are IELTS scores calculated?
Here is a link about how to get your overall scores https://www.ielts.org/ielts-for-organisations/ielts-scoring-in-detail
For Writing and Speaking, the scores you got in the 4 marking criteria are averaged, and your score is rounded down.
For example: TR 6; C&C 7; VOC 7; GR 7 = 27/4 = 6.75 = 6.5
Just take into consideration that the writing score is calculated by adding Task 1 + Task 2 + Task 2 (repeated), which is then divided by 3.
So, if you got 7 for Task 1 and 6.5 for Task 2 6.5 it would be:
7+6.5+6.5 = 20
20/3 = 6.67
Writing band = 6.5