Where do you think is better to make calculations with data? In Controller or in Model?
I think its neither. It is better to have a different service layer for the logic implementations.
The question you ask is related to software architecture and is more philosophical in nature. So I in your place would, probably, edit a question and add architecture, MVC tags.
It is very hard to tell without any information on "data". You need to provide more examples and use cases.
Sergio
Web Developer & curious mind
The best location are none of one. It's interesting to have help classes or application services. I recommend you to read about hexagonal architecture and a bit of DDD, the part of application/domain services that can help a lot. Also a bit of CQRS or CommandBus too.
Here you can read about it, and here some libraries