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

Touch RPN: the RPN calculator for iPhone and iPad

Touch RPN (formerly known as Touch Fin) 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

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Get it at App Store

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


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

Figure 2: Settings pane

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.

Figure 4: Quick guide, shown by touching the right side of the LCD area

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 it, go to Settings and lock the orientation to Landscape.

Figure 5: Vertical layout.


This app implements many RPN flavors. Out of the box, the app offers two free flavors: financial and scientific. Press ON to select the active flavor. To enable a greyed-out flavor, just touch it and confirm the purchase.

Figure 6: RPN flavors menu, accessible by touching ON. In this picture, all flavors are open. In your phone, locked flavors show a purchase price in your local currency.

Figure 7: Financial flavor

Figure 8: Scientific flavor (related to the discontinued 11C)

Figure 9: Advanced financial flavor, with algebraic mode

Figure 10: Financial flavor with Black-Scholes functions

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

Figure 11: Basic scientific (related to the discontinued 10C)

Figure 12: Advanced scientific flavor (related to the discontinued 15C)

Figure 13: Computer programmer‘s flavor (related to the discontinued 16C)

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 14: Advanced Scientific RPN flavor with fast swap buttons enabled.

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

Figure 15: Settings subpanel where the fast swap buttons are chosen.

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

Saving copies of the memory

All RPN flavors can store multiple copies 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 your phones and tablets, you can exchange memories between them.

The keystrokes used to save/load/delete memories are slightly different for each flavor:

Financial flavors

Scientific calculator ("11")

Advanced scientific calculator ("15")

Basic scientific calculator ("10")

Computer programmer's ("16")

More about Settings

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

Using a hardware keyboard

If you have a hardware keyboard connected to your phone, you can use some shortcuts to operate the calculator. Note the shortcuts are different for financial and scientific flavors.

Map 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)

Map for Scientific (11) and Sci Advanced (15)

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 +=

Map for Scientific Basic (10)

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 +=

Map for Computer Programmer flavor (16)

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 +=

Problems with purchases?

From time to time, we get reports from users that had purchased an ad-free flavor, and after some time the app started to show ads again. Normally, this happens after a software upgrade or phone replacement.

The most common cause is simple: when the app is newly installed, the default flavor is financial with ads. To fix this, open the flavors list (ON key) and select the flavor you had purchased before.

Sometimes a purchased flavor does not show as active on the list. Probably due to a temporary network problem, App Store did not download the purchase receipts, and then the app does not "know" which flavors had been purchased. This may happen when there are many phones under the same Apple account, and the purchase takes a while to propagate to all of them.

This situation tends to resolve itself eventually (takes a time between some hours and some days) but it is possible to force a resolution using one of the following methods:

a) Go to the Settings panel (key ON, then 'Settings' at top right corner) and then touch "Restore purchases".

b) If this does not work, remove and reinstall the app.

c) If this does not work either, remove the app, reboot the phone and reinstall the app.

After doing this, don't forget to go to the flavors list once again (ON key) and check that your purchased flavor is available for use.

If none of them work, we suggest contacting Apple support to check if there any other issues with your account, or ask for a refund, at your discretion.

A couple important remarks about app purchases:

1) In App Store, in-app purchases cannot be shared via Family Sharing. This is a platform limitation, not a problem in the app.

2) It is important to emphasize the whole payment processing of purchases is carried out by App Store. The app just initiates the process and is eventually notified of purchase receipts. The app developers have no access to individual transactions' info.

3) Before Dec 22, 2017, the flavors were sold as separate apps. Since then, the flavors were consolidated into a single app. The transition process involved installing the old and new apps on the same phone, and it was finished in late 2019. If you had purchased an old version and lost the transition window, get the purchase details as described in this tutorial and contact us.

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.


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