This is good @honourmaus , that you found such calculator. It's my first time to see such calculator. See my review below :

Pros :

• It has a more simple and elegant design wherein you will not be having hard time in navigating it's calculator function.
• It does automatically computes your bitcoin's value based on it's current market value.
• You can easily set customized colors and text according to your preference so you will have a move convenient way to use the application.
• It does support many curriencies which can be a really impressive kind of application.

Cons :

• Calculator dedicated only for Bitcoin and other crypto currencies.