12Calc is a full version of the well known HP12C for the iPhone and iPad. It also includes an audit tape, unit converter, worksheets, rotated views, user guide and HD graphics optimized for iPad and iPhone retina displays.

•Runs in 64 bit mode on the latest iOS release and new iPads and iPhones.

•Calculations are highly accurate and blazing fast. No more "running" flashing displays for amortizations, depreciation schedules or interest calculations. Work as fast as you can type.

•Audit Tape: The audit tape keeps a record of your calculations. You can review, mail, text, share or print the tape.

•Unit Converter: Convert between a wide variety of common units and currencies. Currency rates can be downloaded from the internet.

•Work Sheets with interactive graphs:
Auto Purchase
Cash Flow analysis
Interest Conversion
Loan Amortization (includes option for Canadian mortgages)

•Views for all orientations: Portrait and landscape renderings of the full keyboard are provided for iPhone and iPad. The iPad version includes slide over and multiple split view displays as well as side-by-side display of the help page, audit tape, tvm mortgage table or program variables.

•Built-in contextual help: Touch the ? key for a description of any keyboard function with examples of use. If you are just learning or can't remember how to use a function- just touch the ? key. Includes tutorials on how to use reverse Polish notation (RPN) and how to solve time value of money problems.

•HD Graphics: Graphics optimized for both retina and standard resolution screens. Choose from multiple color schemes including gold, rose gold, brass, copper, silver and several color tints.

What’s New

Version 2.4

• Updated for (more) changes/bugs introduced by iOS12.3
• Improved currency converter (again)
• Fixed worksheet file save

Ratings and Reviews

4.9 out of 5
107 Ratings

107 Ratings

mctrader123 ,

Greatest Calculator

Ernest Brock has done a phenomenal job with this App.
I first downloaded a version of this years ago when it was offered free for a short time. Then (I believe) HP asked Ernie to make some changes.
I was extremely worried when I updated my first iPhone, because I thought I would lose this App. But it kept on working. Finally with my iPhone 7, I finally broke down to repurchase the newer (and improved) version.

If you are a fan of HP-12C calculator, then you will likely find this App very intuitive, and I won’t go into describing all the ways it can be used.

But some of the novel features include:
* Currency converter, and current currency values can be updated whenever you want.
*. A “tape” feature, so that you can see what an adding machine tape would show if it were part of the HP-12C calculator.

And although I don’t use it for much more than a basic calculator with financial and real estate (loan, mortgage, PV, etc) calculations as I did for years with my regular HP-12C, I can honestly say that I use this App ALL THE TIME, especially during tax season!

Finally, over the years I have had 2-3 emails with Mr Brock, who has always been prompt, honest, and provided me with valuable tips and help. Just what you want with a developer.

So, stop reading, and go buy the App! You will find it very worthwhile1

2020 is here and my earlier review still stands. Great App. Great support. Go get it!

JGRog ,

Absolutely the Best Financial Calculator––and Best Developer

In an earlier review I gave this phenomenal app 5 stars but wanted to give it 100. Now, I want to give it 1,000.

Without any doubt, this is the #1 calculator of its kind on the market in this CPA's opinion. I use this every day for a wide variety of professional and personal reasons, and I still haven’t begun to plumb its depths. In addition to doing all the HP 12-C calculations, it has templates for leases, loans, time value of money, multi-year financial ratios, foreign exchange calculations, etc.

I use the conversions feature to help me with calculations necessary when I fly general aviation aircraft.

One of the best, most useful features is an electronic "tape," which, amazingly, can be e-mailed as a PDF file for printing if need be. This makes the app substantially more valuable than any physical calculator or any comparable app.

When I bought this app for my iPhone, I expected to have to pay again for my iPad, but, no, I could download it onto my iPad for no additional cost. This calculator is outstanding. The developer, Ernie Brock, is a genius. He keeps making his app better and better all while staying ahead of Apple’s iOS changes that impact the functionality of the program.

I recommend this fantastic app HIGHLY. It continues to get me through CPA seasons, and it makes calculations of pilotage and dead reckoning much easier when I plan cross country flights.

LAX20531 ,

Expertly engineered

I’ve tried most of the 12C emulators in the App Store; this app demonstrates the value well-designed engineering can add to a legacy device. This app performs calculations more rapidly than its competitors and the worksheets and scenario guidance are pure genius and take the 12C to a futuristic state most wouldn’t have imagined when the physical device launched decades ago. The virtual audit tape (that supports printing and copy/paste) adds tremendous value in reviewing previous calculations and is saved between sessions.

While this is a niche app in a saturated marketplace, it provides tremendous value for those of us who rely on it. For that reason I would support a subscription model to assure its long term availability if necessary.


Ernest Brock
6 MB

Requires iOS 11.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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