# RPN Calc Pro > Professional scientific calculator using Reverse Polish Notation with a 4-level stack. (iPhone/iPad app by SparkStream, LLC.) - Source: https://appshunter.io/ios/app/rpn-calc-pro/id6757244933 (this page in markdown: same URL + `.md`) - Developer: [SparkStream, LLC](https://appshunter.io/developer/1848634146) - Category: Utilities, Productivity - Price: $2.99 - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 18.5 · 0 MB - Languages: American English - Released: 2026-03-13 - Data updated: 2026-06-05 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/rpn-calc-pro/id6757244933/reviews.md ## What is RPN Calc Pro? RPN CALC PRO - Classic Reverse Polish Notation A professional scientific calculator for engineers, scientists, and RPN enthusiasts. Experience the efficiency of Reverse Polish Notation with a clean, modern interface. RPN Calc Pro is provided for general use. Results should be independently verified for any critical application. SparkStream, LLC is not responsible for errors arising from use of this app. FEATURES: - Full 4-level stack display (T, Z, Y, X registers always visible) - Complete scientific function set - Trigonometric functions (sin, cos, tan, and inverses) - Logarithmic and exponential functions - Power and root operations - Memory storage and recall - Stack manipulation (swap, roll) - Degree mode for all trig functions - Clean, distraction-free interface - No ads, no tracking, no subscriptions PERFECT FOR: - HP calculator users - Engineering students and professionals - Scientists and researchers - Anyone who appreciates efficient calculation methods WHAT IS RPN? Reverse Polish Notation is a mathematical notation where operators follow operands. It eliminates the need for parentheses and allows for faster, more intuitive calculations once learned. NO ADS. NO TRACKING. JUST CALCULATIONS. ## Key features - 4-level stack display - Complete scientific function set - Trigonometric and logarithmic functions - Memory storage and recall - Stack manipulation - Degree mode for trig functions - Ad-free and tracking-free ## Frequently asked questions about RPN Calc Pro ### What is RPN Calc Pro? RPN Calc Pro is a professional scientific calculator that uses Reverse Polish Notation (RPN) for calculations. It offers a clean interface and a full 4-level stack display, making it efficient for complex mathematical operations. ### How much does RPN Calc Pro cost? RPN Calc Pro is a paid application, available for $2.99. There are no subscriptions or in-app purchases required after the initial purchase. ### Does RPN Calc Pro have ads? No, RPN Calc Pro is completely ad-free. The description explicitly states 'NO ADS. NO TRACKING. JUST CALCULATIONS.' ### What devices is RPN Calc Pro available on? Currently, RPN Calc Pro is supported on iPhone devices. The app is rated for ages 4 and up. ### How often is RPN Calc Pro updated? The latest version of RPN Calc Pro is 1.4, which was last updated on March 31, 2026. This indicates a recent update, suggesting ongoing support. ### What kind of functions does RPN Calc Pro offer? RPN Calc Pro includes a complete scientific function set, trigonometric functions (sin, cos, tan, and inverses), logarithmic and exponential functions, and power/root operations. It also supports stack manipulation like swap and roll. ### Is RPN Calc Pro suitable for beginners? While RPN Calc Pro is designed for professionals and enthusiasts, it can be learned by beginners who appreciate efficient calculation methods. The app provides a clean interface to help with the learning process. ### What makes RPN Calc Pro different from standard calculators? RPN Calc Pro uses Reverse Polish Notation, where operators follow operands, eliminating the need for parentheses. This method is often preferred by engineers and scientists for its speed and intuitiveness once mastered. ## Version history (last 5 releases) ### 1.4 — 2026-03-31 • Improved error handling — divide by zero, invalid operations now show a clear "Error" state instead of silent failures • Calculator state now persists between app launches — your stack, memory, and mode settings are saved • Larger, more readable button labels and stack display • Scientific notation entry improved — ± now correctly toggles exponent sign • T-register now replicates after operations, matching classic HP RPN behavior • VoiceOver accessibility support added for all buttons and display registers • Removed unused code and reduced app footprint ### 1.3 — 2026-03-20 Updated app icon. ### 1.2 — 2026-03-15 Updated app description with usage disclaimer. ### 1.1 — 2026-03-14 Redesigned interface with improved layout, larger display, and expanded 2nd function system with DEG/RAD toggle, LASTx, D→R/R→D conversions, and more. ### 1.0 — 2026-02-17 No release notes. ## More apps by SparkStream, LLC - [ABC Letter Match](https://appshunter.io/ios/app/abc-letter-match/id6754522147) All apps by SparkStream, LLC: https://appshunter.io/developer/1848634146 ## Related topics [rpn calc pro](https://appshunter.io/ios/topics/rpn-calc-pro) --- *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 2026-06-05.*