ThetaCalc vs Axiomeer

ThetaCalc is a RPN (Reverse Polish Notation) calculator which can be extended by functions and equations programmed by the user in JavaScript.

Calcula is a powerful scientific calculator that combines classic RPN stack workflow with a full Algebraic (ALG) mode in one app. Designed for advanced users, engineers, students, and technical professionals, Calcula lets you choose the input style you prefer, then move seamlessly between both worlds. Two calculation modes, one engine - RPN mode for fast stack-based operation - ALG mode with scientific keypad and direct expression input - Instant switch between modes from the main interface Advanced algebraic input - Scientific ALG keypad with prefix actions (`f/g`) - Keyboard or keypad entry - Live rendered math preview with pan and pinch zoom - Build, inspect, and refine long expressions comfortably Rich math objects - Real and complex numbers (Cartesian/Polar behavior) - Fractions, vectors, and matrices - Matrix/vector operations including products, transpose, determinant, inverse, dot and cross products Units, constants, and formatting - Integrated units workflow in expressions - Access to constants database in ALG flow - Shared global number formatting between RPN and ALG Functions and persistence - Define and edit functions from both RPN and ALG workflows - Coherent shared function database - Draft and editing improvements for smoother continuity Statistics and scientific tools - Shared statistics memory across RPN and ALG - Statistical operations and previews integrated into ALG workflow - Extended scientific function coverage with ongoing expansion Calcula is built for real technical work: precision, depth, and flexible interaction without sacrificing speed.