# HP16C > HP 16C Computer Scientist calculator recreation with RPN and bit manipulation. (iPhone/iPad app by Michael Doornbos.) - Source: https://appshunter.io/ios/app/hp16c/id6761774728 (this page in markdown: same URL + `.md`) - Developer: [Michael Doornbos](https://appshunter.io/developer/1891405652) - Category: Utilities - Price: Free - Rating: 5.00/5 from 2 App Store ratings - Age rating: 4+ - Requires: iOS 17.0 · 1 MB - Languages: English - Released: 2026-04-08 - Data updated: 2026-06-26 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/hp16c/id6761774728/reviews.md ## What is HP16C? A faithful recreation of the legendary HP 16C Computer Scientist calculator for iPhone, with a few modern upgrades. If you've ever needed to perform hex arithmetic, bit manipulation, or base conversion on your phone and been frustrated by the available options, this is for you. RPN-16C gives you the full power of the original HP 16C in your pocket. WHAT IT DOES - Full RPN (Reverse Polish Notation) calculator - Integer arithmetic in HEX, DEC, OCT, and BIN - Configurable word size from 1 to 64 bits - Unsigned, one's complement, and two's complement modes - Complete bit operations: shift, rotate, rotate through carry, AND, OR, XOR, NOT, mask, bit set/clear/test, count bits, left justify - Float mode with configurable precision (FLOAT 0-9) - Keystroke programming with labels, subroutines, loops, and conditionals - Storage registers with direct and indirect addressing - Programs can be imported from text (long-press the display to paste) ENHANCEMENTS OVER THE ORIGINAL - Two-line display: see both X and Y registers at once. No more guessing what's on the stack. - Wider LCD: displays all 32 bits in binary without scrolling. The original could only show 8 at a time. - Haptic feedback on every key press - State persistence: pick up right where you left off - SHOW function to peek at values in other bases FAIR WARNING This is a quirky calculator. It uses Reverse Polish Notation, has no equals key, and expects you to know what two's complement means. If you're looking for a simple calculator, this is not it. If you've ever wished you could do a bitwise rotate through carry on your phone, welcome home. DESIGNED FOR PROGRAMMERS The key layout matches the physical HP 16C exactly, including the f (gold) and g (blue) shift labels. If you know the original, you already know this one. The original HP 16C Owner's Handbook is freely available on the Internet Archive: https://archive.org/details/hp-16c_handbook ## Key features - Full RPN calculator - Integer arithmetic (HEX, DEC, OCT, BIN) - Configurable word size (1-64 bits) - Complete bit operations - Keystroke programming - Two-line display - Haptic feedback ## Frequently asked questions about HP16C ### What is HP16C? HP16C is a mobile application that provides a faithful recreation of the legendary HP 16C Computer Scientist calculator. It offers advanced features for hexadecimal arithmetic, bit manipulation, and base conversion, designed for programmers and engineers. ### Does HP16C support RPN? Yes, HP16C fully supports Reverse Polish Notation (RPN), which is a hallmark of the original HP 16C calculator. This means it does not use an equals key and expects users to be familiar with RPN input methods. ### What programming features does HP16C offer? HP16C includes keystroke programming with support for labels, subroutines, loops, and conditionals. It also features storage registers with direct and indirect addressing, allowing for complex program creation. ### How does HP16C enhance the original HP 16C? HP16C offers several modern upgrades over the original, including a two-line display to see both X and Y registers simultaneously, a wider LCD that displays all 32 bits in binary without scrolling, and haptic feedback on key presses. ### Is HP16C suitable for beginners? HP16C is designed for users familiar with advanced calculator functions like Reverse Polish Notation and two's complement arithmetic. It is not intended for users seeking a simple, everyday calculator. ### What platforms is HP16C available on? HP16C is available for iPhone and iPad devices, indicated by its support for 'iphone' and 'ipad'. ### How often is HP16C updated? The latest version of HP16C, 1.0.6, was released on June 4, 2026. This suggests a relatively recent update, though the frequency of future updates is not specified. ### Does HP16C have ads? No, HP16C does not contain advertisements. The application is free and does not include any in-app purchases, making it an ad-free experience. ## Version history (last 5 releases) ### 1.0.6 — 2026-06-04 Fixed a crash when you overflowed the largest signed value at a 64-bit word size, for example, adding 1 to 2^63 The bad value got saved too, so the app would crash again on every launch until it was reinstalled. It now rolls over to the most negative number. Thanks to the user who reported it. ### 1.0.5 — 2026-05-25 PSE now pauses for about a second mid-program, as the original HP 16C did, so values shown during a run are readable. SF, CF, and F? With flag 4 or 5 now, toggle the overflow and carry indicators the same way the real machine does. Program memory is capped at 203 steps to match the original. VoiceOver labels were added to every key, so the calculator is usable with the screen reader for the first time. Fixed a small bug where a paused program could resume at the wrong moment after the app was backgrounded. ### 1.0.2 — 2026-05-19 Auto-rotation: iPhone and iPad now support portrait as well as landscape orientations ### 1.0.1 — 2026-04-10 Improved iPad layout: calculator is now centered with proportionally scaled fonts instead of stretching across the full screen. ### 1.0 — 2026-04-08 No release notes. --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-26.*