Yes it is better done in a query. If you have many queries that use one field, I'm thinking that you are unnecessarily duplicating things. You don't create a query for each department/date range/manager etc. that returns the same info - you create one query and provide those parameters in some way. Same goes for reports and forms. If that's not your case then I suppose I might create a query that did my calculations and join that in other queries. Not something I've ever had to do because calculations in one query never had a relationship to those in other tables and I don't duplicate these objects.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.