5 Stars. “I can't tell you how often I use it, probably about as much as the phone app!"
- CharlieW, President. Waterman & Company (Real Estate Investment and Development)

“This is the first 12C type calculator for the itouch that has actually made me put down my real 12C. One of the best features of this calculator is the register display where you can see what is in FV, I, PV, PMT, etc. That alone makes it worth the $14.95 price. Consider the many other features that it has over and above the real 12C and you have one sweet program here. Best of the 12C emulators out there - hands down! “
- tsinvest

It started in early 2008 with a belief that:
• there was one and only one insanely great financial calculator
• the iPhone is the perfect platform to bring that calculator back to life
• it's not good enough to just copy the old, you have to make it better
• a financial calculator is a professional tool, not a game

From this mindset came Calc-12E, the first 12C emulator on the App Store. It was expensive back then ($20-$25) and compared to a game it still is because, well, you usually get what you pay for. Specifically:

Foremost, if the math isn't right in the corner cases I can't trust the calculator. Calc-12E's algorithms were written for iOS by a (the?) key member of the original 12C development team who incorporated his solutions to the quirks in financial computation that historically tripped up lesser implementations. There are reasons the 12C was the absolute best, and Calc-12E draws directly on that heritage.

While the original did what it could, 1980s technology made many features difficult, impractical or impossible to use. Calc-12E pioneered the following innovations to address shortcomings:
• you can always see what's in the financial registers (and stack if you choose) so you have instant assurance that you've entered your data correctly. This feature has been copied by nearly every emulator on the App Store, for good reason.
• visual cash flow editing radically eases how you deal with cash flows... believe it or not it is actually easy to manipulate cash flows with Calc-12E. There's a demo on YouTube, search for Calc12E.
• Investment mode allows you to simultaneously evaluate metrics on up to three cash flow scenarios at a time. You can compare cash flows side-by-side AND because of visual cash flow editing you can play what-if games
• the results of some calculations need to "leave the phone" to be useful. Amortization schedules, leasing terms, bond yields... everything can be sent via email using customizable templates

Finally, a professional tool receives continuing support and updates. It does not nag you to rate it, it does not invite you to pay to get more. It does not crash. Check out Calc-12E's version history and reviews of previous versions. This is a live, supported app with tens of thousands of long term customers and I have never charged for an upgrade or cloaked features behind ads or paywalls. It's not ethical at this level (in my humble opinion!).

When you buy Calc-12E you get my best (and evolving!) rendition of the most popular handheld calculator ever made. It's core (the math) comes from the same mind as your trusty original and to that foundation you get usability advances that actually enhance the overall tool.