RpnCalc 12c Financial Calculator is the highest-rated and most popular financial calculator on the Android Market.
It has an interface that users of the HP 12C financial calculator line will be completely at home with, but does much more. Calculations are far faster, doing in a fraction of a second what the classic calculator could take minutes to compute. It also includes scientific and basic modes.
No ads, no spyware. The only permission it asks for is to save and recall programs.
RpnCalc Financial is a highly versatile full-function programmable financial calculator. It includes math, finance, statistics, and scientific functions.
Features include:
* Time value of money (TVM)
* Amortization
* Cash flow analysis: IRR, NPV
* Bond pricing
* Date and interest calculations
* Percentages, markups, percentage of total
* Scientific mode
* Basic (large key) mode
* 20 Memories
* 99 Program steps
* Key click (haptic feedback)
* Continuous memory
Improvements over the classic HP 12C Financial Calculator:
* 16-level stack (configurable)
* Front four stack elements always displayed
* Programs can be saved and restored by name
* Programs displayed symbolically
* Memories are not sacrificed to make room for program steps
* Full amortization display, register display, NPV display, and program display.
* "Calculator tape" feature records all your actions and lets you share the recording
See http://www.efalk.org/RpnCalcFinancial for a full description and documentation.
RpnCalc Financial has a sixteen-level stack to hold more data. The front four elements on the stack are visible at all times, making it much easier to keep track of where you are in your calculations.
Calculator programs are stored and displayed symbolically, making programming much easier. Programs can be stored and retrieved from the external memory whenever your Android is in file-sharing mode.

If you want to "test drive" a similar calculator before purchasing, try the free "RpnCalc" scientific calculator.
Oh, and here's the privacy policy: RpnCalc never collects any private data of any sort. It never connects to the internet. It doesn't even run ads.