Site menu Touch RPN: the RPN calculator for iPhone and iPad
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Touch RPN: the RPN calculator for iPhone and iPad

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Touch RPN (formerly known as Touch Fin or Touch 11i) is a financial and scientific calculator for iPhone. It implements most features of the industry-standard HP-12C calculator, including programming functions.

Figure 1: Touch RPN main screen, active flavor is Financial Premium

Get it at App Store

Touch Fin uses the same engine of the proven HP-12C Web emulator. It aims to reproduce all features (and limitations) of the real device.

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 as the real 12C: only 99 programming steps, 20 memory positions, etc.

Copy to Clipboard

Touch the upper left corner 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.


This app implements all RPN flavors that used to be sold as premium 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. Press ON to select the active flavor.

Figure 2: RPN flavors menu, accessible by touching ON

To enable a greyed-out flavor, just touch it and confirm the purchase.

If you had bought a premium app, the respective flavor is automatically enabled in Touch RPN. All you need to do is to install the old app on the same phone where Touch RPN is installed, and run the old app at least once. Then, go back to Touch RPN and confirm the flavor is enabled.

The rights inherited from old apps are registered at your Apple account as zero-cost in-app "purchases". They will guarantee that your RPN flavors will remain enabled on your next phone. The App Store will ask for confirmation of these "purchases"; please confirm them to secure these rights.

Likewise, all flavors you purchase will be available on all your iOS devices connected to the same Apple ID, and will continue to be available on future devices.

Available flavors

Figure 3: Free financial flavor

Figure 4: Free scientific flavor (former Touch 11i free app)

Figure 5: Premium financial flavor (former Touch Fin app)

Figure 6: Algebraic/RPN financial flavor (former Touch Fin Palladium app)

Figure 7: 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 8: Basic scientific flavor (former Touch 10i app)

Figure 9: Advanced scientific flavor (former Touch 15i app)

Figure 10: Computer programmer‘s flavor (former Touch 16i app)

Features found in premium flavors

Besides the ad-free experience, many other features are available for the premium (paid) flavors.

Quick guide

Touch the upper right corner of the screen to open a quick guide for some operations of the calculator.

Figure 11: Quick guide, available in premium flavors

Vertical layout

The vertical layout can be more practical if you like to use your phone in portrait orientation.

Figure 12: Vertical layout, available in premium flavors

Increased sensitive area

The area around the keys is also sensitive to touches. You don't need to touch the key spot-on; touching near the key is enough. Coupled with the visual feedback, this feature allows faster typing. (Press RCL g ON if you are curious to see the sensitivity map.)

Save memory

The current calculator memory (including all registers and programming steps) can be saved. You can save as many memories as you want, e.g. if you have many programs and want to load them later.

Each flavor uses different key combos to save memory. Refer to this section to learn them.


The Settings pane has been reformulated in this new version. It no longer follows the old style and no longer adds a pane in System Settings menu.

To open the new Settings pane, press the ON button, then "Settings" at the right top corner, to access the preferences panel.

Figure 13: Settings pane

Saving copies of the memory

Some RPN flavors allow to store and retrieve images of the memory. This is especially useful to have many different programs available and ready to use, as well as to transfer data between devices.

Memories are stored locally as well as in iCloud. If you have configured iCloud in all your phones and tablets, you can transfer memories between them.

The key combinations are slightly different for each flavor:

Financial flavors, including Palladium and Black-Scholes

Scientific calculator ("11")

Advanced scientific calculator ("15")

Basic scientific calculator ("10")

Computer programmer's calculator ("16")

Flavor specifications

Financial calculators: based on HP-12C Web emulator.

Palladium financial calculator: based on HP-12C Platinum Web emulator.

Black-Scholes financial calculator: based on BS-12C Web calculator. In case you are already familiar with HP-12C and/or our calculator, read this manual to learn how to use Black-Scholes features.

Scientific calculators: based on HP-11C Web emulator.

Advanced scientific calculator: based on HP-15C Web emulator.

Basic scientific calculator: based on HP-10C Web emulator.

Computer programmer's calculator: based on HP-16C Web emulator.

Differences from real calculators

First of all, it is important to mention that the calculator engine does not use a ROM dump. It is a clean-room implementation, based mainly on calculator's manual plus experimentation. So the results simply can not guaranteed to be exactly equal. Other differences:

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 app does not send any user data to any remote party, and it does not share operation data with other apps.


Please use the comment section at this page, or contact me by e-mail if you have any issues or feedback.

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