Tabi Calc is a calculator specifically designed for travelers. *Tabi is Japanese for travels.
Arrival time - Departure time = Travel time
Timezones support (City names and 3-digit Airport codes)
Automatically detect GPS and set your local currency.
Easy conversion between local and your home currency (iPhone & Apple Watch)
It also works as a regular calculator:
Arithmetic between two numbers
M+, M- buttons
Time difference between two photos