FAQ

• Results from trigonometric functions are always in RAD.

  Is the Complex mode switched on? The Complex mode is indicated by a "C" in the status bar and can be switched off by g CF 8.

• If I rapidly type a sequence of numbers, the entered keyboard number(s) are ignored. For example, if I type 123 quickly, the 2 is missed and I get 13 on the display.

  While a key on the computer keyboard is being pressed, all other key presses are ignored. When you pressed the 2, you were still holding down the 1. This is exactly how the real HP-15C behaves.

• Where can I see the version number of the simulator?

  The serial number follows the rules for serial numbers of HP calculators of that era. The format is YYWWCsssss with the following meaning:

  • YY = Years since 1960
  • WW = Week of the year
  • C  = Country
  • sssss = a unique serial

  The calculator serial number 6112G04300 means: Built in 2021 (= 1960 + 61) in the 12^th week in Germany. 4.3.00 is the version number.

• The HP logo and the 15C label on the simulator front are missing

  Be sure to uninstall all versions of the "HP15C Simulator Font". Then install the font file from the latest HP-15C package you have downloaded.

• Do you plan to implement other models of the Voyager series, e.g. the HP-12C?

  I don't own any of the other models and I have no plans to implement them.

• How can I exchange the period (decimal point) and the comma (digit separator)?

  Using the mouse: Right-click the ON button or the area around the display and select "Swap comma and period".
  Using the keyboard: Press Alt–. (period) or Alt–, (comma).

• Where can I get a German user manual for the Simulator or the HP-15C Limited Edition?

  The manual for the HP-15C Limited Edition is only available in English. However, the HP-15C LE and the HP 15C CE are functionally identical to the original HP-15C from the 1980s and the Simulator. Therefore the manuals for the original HP-15C also apply to the LE and the Simulator.
  The HP-15C Owner's Handbook in Danish, English, German, French and Portuguese is available on the HP Calculator Literature page.

• Why do some keys show a small square instead of the correct label?

  Please see the Font Settings.

• Do you plan to port the simulator to other operating systems like Android or iOS?

  I do not plan to port it to other platforms. There are several commercial HP-15C emulators available in the iOS and Android app stores.

  I can also highly recommend RpnCalc. It does not have all the features of the HP-15C, but it is free and more than sufficient for everyday use. I use it on all my Android devices.

• Is there a configuration interface or tool to re-map the keyboard shortcuts?

  There is no such thing. The keyboard shortcuts follow standards, like Ctrl–O to open a program, or are straightforward, like E for e^x or S for SIN. The small number of candidates for remapping does not justify the effort.

• I get an error message on macOS when I try to open the DMG file or run the app.

  Unfortunately, with each new version, Apple has decided to make it more difficult to install free software. The two methods described below have worked in the past. However, there is no guarantee that this will continue to be the case in future.

  'HP-15C' is damaged and can't be opened. You should eject the disk image
  This message is reported for macOS Tahoe 26.3.

  • Double-click the DMG file to open it.
  • Do not run the HP-15C application from the disk image.
  • Drag the HP-15C app to the Applications folder in Finder.
  • Open the HP-15C app from the Applications folder in Finder or from the 'Apps' folder in the Dock.
  • You get the following error message: 'HP-15C' is damaged and can't be opened. You should eject the disk image
  • Ignore this message; it is because the app is not fully signed and has been quarantined.
  • Open a Terminal window and run the command xattr -dr com.apple.quarantine /Applications/HP-15C.app.

  "HP-15C.app" cannot be opened because the developer cannot be verified
  The following steps worked in 2025.

  • Go to System Settings

    Click the Apple menu in the top-left corner of your screen.
    Select System Settings (or System Preferences in older versions).
    Navigate to Privacy & Security.

  • Locate the Security Section:

    Scroll down to the Security section.
    If you recently tried to open the app, you should see a message that says, "HP-15C was blocked because it is not from an identified developer."
    Next to this message, there should be an Open Anyway button. Click it.

  • Authenticate and Confirm:

    You may be prompted to enter your administrator password to confirm the action.
    After clicking Open Anyway, you'll see a dialog asking if you're sure you want to open the app. Click Open to proceed.