Qalculate! — The Complete Guide: A Smart Desktop Calculator With Units and Constants
Qalculate! is a desktop calculator that understands units. You can type an expression such as force times lever arm in mixed units and get the result in the unit you choose. It replaces the pocket calculator for quick checks and conversions, and it is open source under GPL-2.0.
Qalculate!
Hanna Knutsson
A smart desktop calculator — full unit conversion, physical constants, uncertainty propagation and symbolic algebra.
Get it from the vendorWhat you get
- Units and conversion — calculate directly with mixed units and convert to any unit.
- Physical constants — available by name inside an expression.
- Uncertainty and intervals — error propagation and arbitrary precision.
- Symbolic operations — solving equations, differentiation and integration.
- Plotting — draw functions straight from the calculator.
How to use it
There is a GTK interface, a Qt interface and a command-line version, for Windows, macOS and Linux. You type an expression on one line and get an instant answer, with a history of earlier calculations. For a quick check of a result from a program or a spreadsheet, it is the tool you open first.
Related tools
For a documented calculation sheet with units — EngineeringPaper.xyz. For full symbolic algebra — wxMaxima. For MATLAB-style numerical work — GNU Octave.
EngineeringPaper.xyz
Engineering Paper LLC
An engineering calculation sheet in the browser with automatic unit checking and conversion, equation solving and plots.
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wxMaxima — Symbolic Algebra
Maxima Project / wxMaxima
Graphical front end to the Maxima computer algebra system — derivatives, integrals and equations in mathematical notation.
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GNU Octave
GNU Project
Numerical computing in MATLAB-compatible syntax — matrices, equations, signals and plots.
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GeoGebra
GeoGebra
Graphing, geometry, CAS and 3D calculator in one place — for quick checks of functions, geometry and symbolic calculations.
Get it from the vendorThe bottom line
Qalculate! is a calculator that stops unit mistakes before they enter a calculation. Free, light and fast — it deserves to be open on every engineering computer.