Harry Potter Currency Calculator/Converter: Daily Challenge 004

I loooove Harry Potter and Im in the process of Re-reading the books (again) and thought a fun idea for the daily challenge would be to create an official Ministry of Magic app for Wizards that would help them calculate & convert wizarding money into muggle money & vice versa (Keeping up with those pesky exchanges can be difficult!)

This app would be used in a world where muggles are aware of the wizarding world and wizards have mobile phones of course.

I didn't have as much time for this idea as I would have liked but what do you guys think? :)