RCalc is an RPN (Reverse Polish Notation) calculator. It aims to be quick to open and use, and easy to extend with new types, operators, and commands.
RCalc supports some command line options. It also has a graphical frontend.
This is free and open source software.
Key Features
- 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 – understands 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, RCalc can promote up to BigInts to avoid floating point imprecision
- 84 built-in operators.
- All the expected operators (basic arithmetic, exponents, logarithms) are present.
- 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).
- 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.
- Recognizes values represented in binary, octal, decimal, and hexadecimal:
- 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 hexadecimal when working with colors.
- Cross-platform support – runs under Linux, macOS, and Windows.
Website: git.sr.ht/~jamis/rcalc
Support:
Developer: Patrick Gelvin
License: MIT License

RCalc is written in C++. Learn C++ with our recommended free books and free tutorials.
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