Site menu Touch RPN: the RPN calculator for Android

Touch RPN: the RPN calculator for Android

Touch RPN (formerly known as Touch Fin) is a financial and scientific RPN calculator for Android. It implements most features of the industry-standard HP-12C calculator, including programming functions.

Figure 1: Touch RPN screenshot

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Get it on Google Play

The calculator mimics the real device as closely as practically possible, including details such as rounding up of n in financial calculations. It shares the same limitations of the real 12C: only 99 programming steps, 20 memory positions, etc.


Press ON to open the Settings pane.

Figure 2: Settings pane. Press ON to open this pane.

In this pane you also find the options to save/load/delete copies of the memory to files, and change the RPN flavor.

Copy to Clipboard

Touch the left side of the LCD area to copy the displayed value (the X register) to the clipboard. A feedback alert is shown on screen.

The value is copied in a "spreadsheet-friendly" format: no thousand separators and point as decimal separator.

Figure 3: Touch around the red area to copy number to clipboard, touch around the green area to open the quick guide.

Quick guide

Touch the right side of the LCD area to open a quick guide for some operations of the calculator.

Figure 4: Quick guide

Vertical layout

The vertical or portrait layout can be more practical if you like to use your phone in portrait orientation. If you don't like, you can go to Settings and lock orientation to Landscape.

Figure 5: Vertical layout


This app implements many RPN flavors. They used to be sold as apps: Touch Fin, Touch Palladium, Touch Fin Black-Scholes, Touch 10i, Touch 11i, Touch 15i and Touch 16i.

Out of the box, the app offers two free flavors: financial and scientific. To change the active flavor, press ON to go to Settings, touch the option "Choose flavor" and select the desired flavor.

Figure 6: Menu of RPN flavors.

The flavors "Financial Premium" e "Scientific Premium" are functionally equal to the free flavors, except they are ad-free.

Ready-to-use flavors are shown without a price. Flavors available for purchase show a price in your currency. If you want to release a flavor, touch it and follow the Google Play instructions. Once the purchase is confirmed, the flavor is activated right away.

Fast swap of flavor

If you have purchased two or more RPN flavors, you can activate the fast swap buttons. They are shortcuts to exchange between e.g. financial and scientific flavors without having to open the Settings panel.

Figure 7: Advanced Scientific RPN flavor with fast swap buttons enabled.

The fast swap shortcuts can be configured via the "Flavor fast swap buttons" panel of Settings. At most three flavors can be enabled to have shortcuts, and at most two shortcuts are shown on the main screen.

Figure 8: Settings subpanel where the fast swap buttons are chosen.

The fast swap buttons are completely disabled when any free flavor is in use.

Migration from legacy apps

Premium RPN calculators used to be sold as separate apps. If you had purchased any of them, it is easy to transfer your purchase to this app. For example, if you had bought Touch Fin Palladium, install it on the same phone, then come back to the new app, open Settings and Choose Flavor. The "Financial Advanced" flavor should be open for use.

Once you have confirmed the flavor is open, you can remove the old app. If you get a new phone, or if you have many phones, repeat the process on each phone.

The legacy apps are no longer sold but they remain in the "My Apps" section of your Google Play, and you can keep using them. Just keep in mind they are not being updated anymore.

Available flavors

Figure 9: Financial flavor (former Touch Fin app). Available in two forms: free and ad-free.

Figure 10: Advanced financial with algebraic mode (former Touch Fin Palladium app)

Figure 11: Scientific flavor (former Touch 11i app). Available in two forms: free and ad-free.

Figure 12: Financial flavor with Black-Scholes (former Touch Fin BS app)

The Black-Scholes flavor is "apocryphal" — there has never been a physical calculator with this layout. Read this instruction page to see how it works.

Figure 13: Basic scientific flavor (former Touch 10i app)

Figure 14: Advanced scientific flavor (former Touch 15i app)

Figure 15: Computer programmer‘s flavor (former Touch 16i app)

Save memory to file

The current calculator memory (including all registers and programming steps) can be saved to files, and reloaded later. For example, you can create a library of programs and load one at a time, and even share them with your friends.

The memory saving operations can be found at the top of Settings pane. Press ON and look for the top 3 items.

Figure 16: Options to load, save and delete copies of the memory. They can be found at the top of the Settings pane.

The memory files are saved on "External storage" area, and you can manipulate and share these files, copy to your PC, copy to another phone, etc.

More about Settings

This is a detailed description of each item in Settings pane.

Using a hardware keyboard

If you have a hardware keyboard (USB or Bluetooth) connected to your phone, you can use keyboard shortcuts to operate the calculator. Note the key shortcuts are different for every flavor, as shown below.

Shortcuts for all financial flavors

N I P M V H 7 8 9 /: ! \ # $ % E 4 5 6 X* [ ] D Y C return space 1 2 3 - O F G S R 0 . W += Z: correct typing (rubout)

Shortcuts for Scientific, Sci Premium and Sci Advanced flavors

A B C !D \E H 7 8 9 /: ] T I J K P 4 5 6 X* [ U N Y Z return space 1 2 3 - O F G S R 0 . W +=

Shortcuts for Scientific Basic flavor

A B C !D \E H 7 8 9 /: $#% T I J K P 4 5 6 X* [ ] N Y Z return space 1 2 3 - O F G S R 0 . W +=

Shortcuts for Computer Programmer flavor

A B C D E F 7 8 9 /: U T I J K L 4 5 6 X* [ ] N Y Z return space 1 2 3 - O M G S R 0 . H +=

Terms of use

The calculator is offered "as is". There are no guarantees of precision, exactness, or aplicability to any given purpose. The developer has no responsability for any damages incurring from usage of this software. Always double-check results against other sources if you are going to take some actual financial decision!

Privacy policy

The ad-supported flavors of this app collect and transmit the Advertising ID, exclusively for advertising and analytics purposes.

Apart from that, this app does not send any other user data to any remote party, and no data is shared with other apps.

When the user saves copies of the memory, they are written as files in the "storage area". Files in this area can be manipulated by any other app installed on the same phone. If this is a problem, remove these files from the SD Card once they fulfill their intended usage.


If you have any issues, or just want to send some suggestion or feedback, you can visit the users' group on Facebook, comment at the end of this page, or contact us by e-mail.

Rhino Javascript engine

This calculator includes the Rhino Javascript engine. The engine is released as free software (MPL 2.0 license).