Triangulation is a mandatory calculation rule effective 1st January, 1999. The reason why you have to use triangulation when converting monetary values with European countries' currencies is that there will be no direct exchange rates for countries that take part in the EMU (European Monetary Union). For example, there will be no direct exchange rate for Sterling to Deutschmarks.
The following table is intended to give you an overview of when you need to use triangulation:
| From | To | Use | Example |
| Non-euro European | Non-euro European | Triangulation | DKK -> FRF |
| Non-euro European | Non-European | Triangulation | DKK -> USD |
| Non-European | Non-euro European | Triangulation | USD -> DKK |
| Non-European | Non-European | Division | USD -> CHF |
| Non-euro European | Euro | Division | DKK -> EUR |
| Non-European | Euro | Division | USD -> EUR |
| Euro | Non-European | Multiplication | EUR -> USD |
| Euro | Non-euro European | Multiplication | EUR -> DKK |