Years have gone by since suggesting calculated fields ... so well this is the ultimate idea for many use cases.

Pipedrive maybe able to offer a solution to one of the user cases "Common Currency" before developing full calculation capabilities.

My organisation is a listed company with sales regions around the world as such there is a default currency for financial information, deal values, forecasting e.t.c. 

Pipedrive should create a new custom field that allows for the creation of a new field that is based on the selection of an existing "Monetrey field" and selection of a Currency from the Currency table to convert the Monterey field too, this would allow users to create reports, views at deal level detail in a Common Currency.