Multi-currency — Rollups, lookups and formulas

A computed column that produces money converts, and it converts the same way everything else does: every contributing record at its own date and its own currency, before anything is added up. A Total orders rollup over a linked table of pounds, euros and dollars is one figure in one currency, not three kinds of number added together. The converted figure is the value, and what it was converted from is printed beside it — “$1,714.50 (£1,350.00)” — wherever there is one original to name. A rollup whose contributing records span three currencies has no single original, so it says nothing rather than picking one. The same is true of a lookup pulling one record's amount onto another row: you see the converted amount and the figure the record actually carries.