Site menu Touch 11i: the scientific calculator for iPhone and Android
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Touch 11i: the scientific calculator for iPhone and Android

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Figure 1: Screenshot of horizontal layout - iOS

Figure 2: Screenshot of horizontal layout - Android

Touch 11i (formerly named EPx11C or Andro11C) is a scientific calculator for Android, iPhone and iPad. It implements most features of the beloved HP-11C, including programming functions. The app uses the same engine of the HP-11C Web emulator. It aims to mimic all features (and limitations) of the real device.

Get it at App Store

Get it on Google Play

Emulators of Hp-1xc RPN calculators by EPx

Figure 3: Some reviews from happy users!


The calculator mimics the 11C as closely as practically possible. It shares the same limitations as an original 11C: 399 programming steps, 20 memory positions etc.

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

Figure 4: Touch 11i - quick guide

Touch the upper left corner to copy the displayed value (the X register) to the clipboard. The value is copied in a "spreadsheet-friendly" or "data entry-friendly" format, that is: no thousand separators and point as decimal separator.

Settings (iPhone version)

Figure 5: Touch 11i - Settings

When installed on an iPhone, this app adds a panel to Settings. There you can change the decimal separator and configure typing feedback (audible and visual). The speed execution of a program is, by default, similar to a real calculator's speed; turn on the "Fast" switch to run a program in a faster pace.

The ON key is a shortcut to the Settings panel.

Saving copies of the memory

The app allows to store and retrieve copies of the memory.

This is especially useful to have many different programs available and ready to use (perhaps the programs would not fit in the memory all at once, or it is simply inconvenient to have them all in the same memory image). In any case, the whole memory, including all registers and configurations, is saved along with the program.

Saving copies of the memory in the iPhone

Use the following key combinations to access this feature: The memories are stored locally as well as in iCloud. If you have configured iCloud in your devices, you can transfer memories between devices, provided that they are configured with the same iCloud account. Also, a new device will have access to the previously saved memories, so you don't lose anything when you exchange your old iPhone.

In Android, the app implements a menu that is accessible by touching the upper left corner of the screen, or by keying RCL EEX.

Vertical layout

The app offers an alternative vertical layout. It may be more practical if you prefer to work with the phone in vertical (portrait) position.

Figure 6: Screenshot of vertical layout

By default the layout follows automatically the phone's orientation. If you prefer to use a single layout all the time, you can lock it to vertical or horizontal at Settings (iPhone) or in the menu (Android).

Differences from real calculator

First of all, it is important to mention that the calculator engine does not use a ROM dump. It is a clean-room implementation. So the results simply can not guaranteed to be exactly equal. Known deviations:

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.


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

Privacy policy

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

In Android, 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.

Source code

The source code of this software can be found at GitHub repositories for iOS and Android. The license is similar to Briefs'.
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