ThetaCalc

ThetaCalc

by Felix Stehli

4 ratings
3 reviews
Free

Details

  • Released
  • Updated
  • July 6, 2020
  • May 17, 2026

Features

ThetaCalc screenshot #1 for iPhone
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ThetaCalc screenshot #8 for iPhone
iphone
ipad
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About

This utility app provides a Reverse Polish Notation (RPN) calculator. Users can extend its functionality by programming custom functions and equations using JavaScript.

Reverse Polish Notation (RPN) calculator
User-programmable functions
JavaScript equation support
Extensible functionality
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What's New in ThetaCalc

2.0

May 17, 2026

Improved JS editor (syntax highlighting, auto indenting)

User reviews

Like HP42 or DM42 with Javascript

This calculator is an RPN calculator like the HP42S or DM42 but instead of RPL it uses Javascript for its programming model. This is seriously amazing! I have a bunch of other RPN calculators for iOS and this one blows them all out of the water in every way.

Wow

Didn’t take long to figure out, seems to go ok, like the JavaScript code feature + clear examples. A very tuneable calculator (3,2,1++=) rpn. Luv it. Luv it.

Well thought out JavaScript extensible RPN calculator

There’s no end to what you can do with this calculator!

If you need a calculator to do something unique, you can probably get it done with ThetaCalc.

I wanted to generate a specialized flightplan for an online flight simulator. No problem, ThetaCalc was up to the task. Then for maximum usability, I needed to generate the output as an XML file. Once again, no problem.

It’s so sweet to have this programmability in the palm of your hand.
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Developer apps

FAQ

What is ThetaCalc?

ThetaCalc is a free utility app that functions as a Reverse Polish Notation (RPN) calculator. It allows users to extend its capabilities by programming custom functions and equations using JavaScript.

What devices does ThetaCalc support?

ThetaCalc is available for iPhone and iPad devices. It is designed for users who need a powerful and customizable calculator on their Apple mobile devices.

How often is ThetaCalc updated?

The latest version of ThetaCalc is 1.9, released on September 16, 2025. While specific update frequency isn't detailed, the app has received updates since its initial release on July 6, 2020.

Is ThetaCalc suitable for children?

ThetaCalc has an age rating of 4+, making it suitable for a wide range of users. Its utility functions are generally appropriate for educational and personal use.

Can I program my own functions in ThetaCalc?

Yes, a key feature of ThetaCalc is its ability to be extended by functions and equations programmed by the user in JavaScript. This allows for highly customized calculations.

Does ThetaCalc have ads?

No, ThetaCalc is completely ad-free. As a free application, it does not display any advertisements, providing an uninterrupted user experience.

What is the user sentiment for ThetaCalc?

ThetaCalc has a positive user sentiment, reflected in its rating of 4.3 stars from 4 ratings. This indicates that users who have reviewed the app generally find it to be a useful and well-functioning utility.

What is the price of ThetaCalc?

ThetaCalc is available for free. There are no costs associated with downloading or using the core functionality of the RPN calculator and its JavaScript programming features.