iPhone Screenshots


CALX is an RPN calculator — a calculator designed to work with a list of numbers.

This means that instead of just typing an equation into your calculator, you push numbers onto a stack, and then apply operations to the lowermost numbers in the stack.

It's bizarre, but it makes sense once it clicks.

If this all sounds confusing, don't worry! CALX comes with a guided tutorial which will get you up to speed in three minutes.


• Gestural interaction: Manipulate your data with simple, intuitive gestures.
• Multiple keypads: CALX features an array of basic, scientific, and statistical functions.
• Customization: Select from different fonts and colours to find a combination that works for you.

What’s New

Version 1.2.1

- Fix font issues on iOS 13

Ratings and Reviews

5.0 out of 5
2 Ratings

2 Ratings

Royalstream ,

Exactly what I was looking for.

I’ve been looking for a stack-based calculator like this for quite a while, resembling how RPL (not RPN) calculators like the HP48 used to work.
If you have never used a calculator like this, give
it a try. This type of calculator becomes so addictive that you’ll never want to use anything else.

zerrer ,

Absolutely perfect

Takes a scary concept and makes it beautiful and simple. The only calculator I'll ever need. Wonderful job!

App Privacy

The developer, Daniel Clelland, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You May Also Like