iPhone Screenshots


allRPNCalc is a versatile calculator that uses the powerful Reverse Polish Notation logic system combined with an automated 4 level stack to compute answers to complex mathematical problems. The keyboard layout and display have been optimized for use on an iPhone,iPod Touch and iPad. Large keys with sound feed back give you typing confidence and the last function keyed is always displayed. Functions are logically laid out to eliminate multiple key entry for most problems.

Display: Results are displayed in fixed, fraction, scientific or engineering notation with from 0 to 14 significant digits displayed. In programmer’s mode hex, decimal, octal or binary (with windowing) can be displayed. Calculations are carried out in industry standard IEEE double format with 14+ significant digits and exponents ranging +/-308.

Math: +, -, ×, ÷, ln, log, e^x, 10^x, y^x, x², x³, 1/x, √x, ∛x, fraction part, integer part, absolute value, random, seed, mod

Trigonometry: sin, cos, tan, asin, acos, atan, sinh, cosh, tanh, asinh, acosh, atanh, to radians, to degrees, to rectangular, to polar, to hours, to hours minutes seconds, hours minutes seconds add and subtract, triangle solver, π, π/2. Trig functions can be computed in radians, degrees or gradians.

Statistics: sum plus, sum minus, mean, weighted mean, standard deviation, population standard deviation, linear estimate x, y and correlation coefficient, combination, permutation, factorial (gamma), percent, delta percent, percent of total

Programer’s functions: and, or, xor, not, shift left, shift right, rotate left, rotate right, word sizes 8, 16, 32, 48

Conversions: 47 world currencies and over 100 commonly used metric, english and other conversion factors used in scientific, engineering and financial calculations.

Financial: time value of money calculations, n, i, pv, pmt, fv, depreciation (straight line, sum-of-years, declining balance), bond price and yield to maturity, amortization, net present value, internal rate of return, up to 80 cash flows, days between dates, date plus days, rounding.

Storage: 4 level automatic stack with lastX, exchange and roll down, 20 general purpose storage registers, register arithmetic +,-,×,÷ , 6 dedicated registers for statistics, 80 cash flow entries, 5 financial registers.

What’s New

Version 4.2

•Update for iOS11

Ratings and Reviews

4.9 out of 5
49 Ratings

49 Ratings

Fan of RPN ,

Useful update to an excellent app

The help button (?) is well thought out as is the calculator. I've installed a number of calculatotrs and removed most but there are two calculators that i will not remove: allRPNCalc and PCalc. If you want to transition from an algebraic calculator to an RPN calculator, start with PCalc and when you are comfortable install allRPNCalc.

By the way, RPN is a superior logic system because when you press an operator button (+, -, X, /, square root, sine, cosine,...) an operation takes place immediately. That is not the case with an algebraic system. Sometimes an operation is delayed, sometimes it takes place immediately.

Neptue ,

Outstanding RPN calculator...

If you like HP calculators, this app should serve you well.

I have been using this calculator for years, and it remains one of my all time favorites. It takes a successful HP calc and adds several useful features: unit conversions, currency exchange rates. I also value its ability to perform scientific and financial calculations.

I have tried and used more than 20 calculator apps. Some do offer features not in this one. However, it is in my top two calculator apps.

So glad the developer has updated this app to be compatible with current iOS versions. Hope other legacy app developers will do the same. The fear of losing this one kept me from being willing to update to the latest iOS.

UPDATE: Been using this great app for years, and it never lets me down! Kudos to the developers who have kept this app working throughout all the many iOS changes by Apple.

MP35217 ,

allRPNCalc - the best

I have bought very few apps for my phone. The purchase of allRPNCalc is the exception. I spent a few dollars on this several years ago and it is the best use of money for an accessory ever. A powerful RPN calculator, that does everything I need and more. It is regularly updated to keep it in sync with all the updates iOS undergoes. I highly recommend this app to anyone that needs an RPN calculator. You will not find better.


Ernest Brock
1.9 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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