PocketEngineer

RPN calculator & date math

Free · In-App Purchases · Designed for iPad. Not verified for macOS.

A classic RPN calculator, handcrafted the old way. PocketEngineer works like the legendary HP pocket calculators: a four-register stack (X, Y, Z, T), Enter instead of equals, and every keystroke exactly where your thumbs expect it. Built by an engineer who has used RPN for forty years — first in C++, now ported by hand to Swift. WHAT MAKES IT DIFFERENT • Date & duration arithmetic — subtract two dates and get days and hours, add 90 minutes to a timestamp, count the days until Christmas. Time math is a first-class citizen, not an afterthought. • The Tape — a paper-tape history of every calculation. Tap any line to rewind the stack to that exact point. The tape never lies: even rewinds are logged. • Real RPN — 4-register stack, Swap, Roll, Drop, stack always visible. • Scientific board in landscape — trig, logs, powers, constants. Portrait stays a clean, plain calculator. • 10 memory registers, persistent between launches. • Hardware keyboard support on iPad. HONEST SOFTWARE Free forever. No ads, no tracking, no accounts, nothing locked. If you enjoy it, there is a small tip jar behind the info button — that's all. Handcrafted by M. Biermaier.

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The developer, Ing. Markus Biermaier, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

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    Information

    Provider
    Ing. Markus Biermaier
    Size
    3.8 MB
    Category
    Utilities
    Compatibility
    Requires iOS 15.0 or later.
    • iPhone
      Requires iOS 15.0 or later.
    • iPad
      Requires iPadOS 15.0 or later.
    • iPod touch
      Requires iOS 15.0 or later.
    • Mac
      Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Age Rating
    4+
    In-App Purchases
    Yes
    • Full Breakfast $4.99
    • Cappuccino $2.99
    • Espresso $0.99
    • Learn More
    Copyright
    © 2026 Ing. Markus Biermaier
  • Developer Website
  • Privacy Policy

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