CalcStak

A RPN Calculator

Only for iPhone

Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.

iPhone

Built for people who think in stacks. No equals key, no parentheses — just clean RPN math, history, and a keyboard that gets out of your way. A reverse-Polish-notation calculator built for the keyboard-first crowd: enter, op, done. No equals key, no parentheses, no nested expressions to babysit. WHY RPN If you've used an HP-12C, a Forth REPL, or any stack-based calculator, you already know: RPN is faster once your fingers know the moves. This app puts that experience on your phone without the skeuomorphic clutter. FEATURES • Stack display - see four levels at a glance, scroll deeper. • Full keyboard - numeric pad, operators, and stack manipulation (swap, drop, roll, LASTX). • Configurable angle mode (degrees / radians), stack mode (unlimited or HP-classic four-deep), and ENTER behavior. • Storage registers (STO/RCL 0–9) for holding values across calculations. • History - every operation, scrollable; tap a row to push that past result onto the stack. Capped at the most recent 150 entries. • Optional Scientific pack (one-time in-app purchase): trig + inverses, log/ln, 10^x/e^x, powers, roots, π and e. • Dark mode and a calm, monospace-forward design. • Offline-only. No tracking, no analytics, no network calls. Your math stays on your phone. NOT INCLUDED (BY DESIGN) • No "infix mode." This is RPN. If that's not what you wanted, this isn't your app. • No cloud sync. Yet. • No ads, ever. PRIVACY CalcStak collects nothing. The app does not make network requests. Settings and history are stored on-device.

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

  • Data Not Collected

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    Accessibility

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    Information

    Seller
    JOEL ANDREW ROSINBUM
    Size
    1.3 MB
    Category
    Utilities
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    • Mac
      Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    © 2026 Joel Rosinbum
  • Developer Website
  • Privacy Policy

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