Not sure, but I don't think it's that easy, considering the currency conversions are constantly changing, you'd need some sort of database where the conversions are constantly updated. Assuming you want it as accurate as possible. I'm sure the conversion doesn't change too drastically from day to day, but you'd still want it to change automatically after however long, without you going in and changing something.
You said you wanted to create it, so I'm assuming youre going to code it. If youre looking for a program that can do it, then I don't know...