Qalculate! (GTK UI)

What is Qalculate! (GTK UI)?

Qalculate! is a long-standing, mature calculator that goes far beyond basic arithmetic. It handles symbolic calculations, integrals, and equations, while also managing unit conversions and physical constants. The project has a solid history, ensuring stability and a deep feature set that rivals specialized math software.

It is ideal for students, engineers, and developers who need more than a standard calculator. If you frequently deal with complex formulas, scientific units, or need to verify calculations with high precision, this tool saves you from switching to heavy-duty math packages.

Compared to the Windows Calculator, Qalculate! feels less like a simple utility and more like a scientific instrument. The GTK interface is straightforward, but the depth of features means you might spend time learning its syntax. It is verbose where Windows Calc is minimal, offering power at the cost of immediate simplicity.

Best for: Users who need a capable scientific calculator that handles symbolic math and unit conversions without switching applications.

Key features of Qalculate! (GTK UI)

• Symbolic calculations including integrals and equations
• Extensive unit calculations and conversion library
• Arbitrary precision and uncertainty propagation
• Interval arithmetic support
• Built-in plotting capabilities
• Large library of customizable functions
• Physical constants database
• Cross-platform compatibility

Tips for Windows users

If you are used to the Windows Calculator, note that Qalculate! uses a more mathematical syntax for input. For example, you might need to specify units explicitly in conversion tasks. There are no direct file format dependencies, but if you have saved calculation histories, you will need to re-enter them. The workflow is more linear: you type complex expressions directly rather than clicking through menus for every operation. Familiarize yourself with the function library to maximize efficiency.

Recent releases

• 5.13.0 — October 5, 2026

  Changes: - Add temporary check box to function edit dialog - Fix bookmark removed when deleting history item immediately above - Fix segfault when adding bookmark to most recent history item - Fix calculate as you type result cleared or added to history again…

• 5.12.0 — July 13, 2026

  Changes: - LaTeX input and output (using latex() function or "$\...$" syntax) - Solve a*x^b+c*d^x=0 for real x - Solve equations with absolute value and complex x (x*abs(x)=a, x^2*abs(x)=a, and a*f(x)+b*abs(x)=c) - Improve simplification of a^(c/d)/b^(c/d) in…

• 5.11.0 — May 25, 2026

  Changes: - Add set functions (union, intersect, setdiff, setxor, isMember, isSubset) and operators (∪, ∩, ∖, ⊖, ∈, ⊆, etc.) - Add characters(), count(), digitSum(), and digitalRoot(), find(), popCount(), string(), and while() functions - Support negative row…

• 5.10.0 — March 30, 2026

  Changes: - Improve factorization and simplification (particularly with radicals, logarithms, and absolute value) - Add ton of refrigeration, slug, mol/dm³, mol/L, and molar units - Add pcm, ppm, ppb, ppt, and ppq (parts per …), and lakh and crore variables -…