Our verdict: Qalculate! is the most capable free calculator for Windows: type an expression in plain notation and it handles units, currencies, fractions and equations. Casual users may never need half of it, and the dense interface takes time to learn.
About Qalculate!
Qalculate! is a multi-purpose desktop calculator. You type expressions in natural notation, such as 5 ft + 30 cm to m or 100 USD to EUR, and it calculates with units, physical constants and currencies with up-to-date exchange rates. A large library of customizable functions covers algebra, calculus, statistics, dates and number bases, and you can define your own variables and functions.
It also does symbolic calculations, including integrals and solving equations, with arbitrary precision, uncertainty propagation and interval arithmetic. The Windows package contains the Qt and GTK interfaces plus the command-line calculator, and a portable zip is available too. Qalculate! is free software under the GNU GPL v2 or later.
What it does well
- Units and currencies. Converts between thousands of units and currencies inside any expression.
- Symbolic math. Simplifies, factors, differentiates, integrates and solves equations.
- Arbitrary precision. Exact fractions and high-precision results with uncertainty propagation.
- Function library. Hundreds of built-in functions plus your own variables and functions.
- Plotting. Plots functions and data sets using Gnuplot.
Who it is for
Good fit
Students, engineers and anyone who wants unit-aware calculations and algebra in a fast desktop calculator.
Look elsewhere
People who want a simple Windows Calculator replacement with big buttons only.
Pros and cons
Pros
- Free and open source
- Units, constants and currencies in any expression
- Symbolic algebra and equation solving
- Portable version available
Cons
- Interface is dense with options
- Windows build requires Windows 10 version 1809 or newer
- Developer notes it still needs more testing and gives no guarantees
How to install Qalculate!
The download button fetches the 64-bit MSI installer from the official GitHub release linked on qalculate.github.io; a portable zip is offered on the same page, and winget install qalculate works too. Currency rates are updated from the internet when you allow it.
Questions about Qalculate!
Is Qalculate! free?
Yes. Qalculate! is free and open source under the GNU GPL v2 or later.
Can Qalculate! convert currencies?
Yes. It converts between currencies using exchange rates downloaded from the internet.
Which interface does the Windows version use?
The Windows package includes both graphical interfaces (Qt and GTK) and the command-line calculator.
