One friend told the difference is as follows,
Something is ‘unexplainable’ means that it cannot be explained. That does not necessarily mean that it does not have an explanation - we just don’t know what the explanation is.
‘Inexplicable’ means that it does not have an explanation at all.
Another person told both mean the same.
Please explain.
‘Unexplainable’ refers to something that literally can’t be explained and this could be in the area of human behaviour or in the natural world where science can’t give an answer.
‘Inexplicable’ has a more figurative sense and refers to something that’s so difficult to accept or credit that you find it difficult to understand. This could describe the unusual act someone has committed that is totally different from the way that they usually behave.