SwiftRPN vs CalcStak

SwiftRPN is an RPN (Reverse Polish Notation) calculator that aims to be quick to open and easy to use. = RPN Stack Work quickly and efficiently using the RPN Stack by pushing and popping values. The stack will always show what series of inputs led to each output, so you won't lose context during complicated expressions. = Extended Types SwiftRPN can understand scalar types like integers and real numbers, as well as vectors and square matrices of sizes 2, 3, and 4. When operating purely in the scalar integer domain, SwiftRPN can promote up to BigInts to avoid floating point imprecision. = Operators SwiftRPN has 84 built-in operators with included documentation and examples. All the expected operators (basic arithmetic, exponents, logarithms) are present, as are: - Rounding functions (floor/ceil/trunc/round) - Unit conversions - Bitwise operations (and/or/not/xor/shift left/shift right) - Statistics (avg/min/max/sum/std dev/NPV) - Trigonometry (sin/cos/tan + arc/hyperbolic variants) - Vector operations (dot/cross/normalize/length/swizzle) - Matrix operations (identity/inverse/transpose + translation/scale/rotation matrix generators) = Unit Conversions SwiftRPN has 74 built-in units, and can convert between units within families, including: - Angle - Area - Colors (3 and 4 components) - Coordinate systems (2D and 3D) - Length - Mass - Storage (Base 10 [SI, 1000 bytes in a kb] and Base 2 [1024 bytes in a kb]) - Temperature - Time - Volume = Value Representation SwiftRPN recognizes values represented in binary, octal, decimal, and hexidecimal. You can: - Enter values in one representation, and convert them to another - See the result of bitwise operations in binary automatically - View vec3 and vec4 components (truncated) in hexidecimal when working with colors.

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.