Numbat review
A free, open-source calculator for precise expressions, unit conversions, and custom functions.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Numbat combines a scientific calculator with a statically typed programming language, available through web and command-line interfaces. It is suited to users who need high-precision expression evaluation alongside physical dimensions and unit conversions, and who are comfortable defining functions or variables. The web version runs through WebAssembly, while installable binaries are available for Windows, macOS, and Linux. Numbat is open source and has a free plan, making it an option for individual users and small teams seeking a calculator they can also program.
Its standout focus is dimensional calculation. Numbat supports comprehensive units, custom units and dimensions, and unit and currency conversions, as well as date and time calculations. Expressions can use user-defined, generic, and recursive functions; the language is statically typed with type inference. Unicode input and tab completion support entry, while documentation covers syntax, a standard library, tutorials, customization, and editor integration. That breadth suits repeatable calculations where units and reusable expressions matter more than a conventional button-based calculator workflow.
The trade-off is scope: Numbat does not support complex numbers, vectors or matrices, or equation solving, so users who depend on those capabilities should choose another scientific calculator. Its support is community- and documentation-based. For people who want high precision, extensive unit handling, and programmable calculations across web and desktop, Numbat is a focused fit; users looking for a broad, conventional scientific calculator or built-in equation-solving tools should look elsewhere.
Numbat pros and cons
- Where it wins
- Evaluates high-precision expressions with physical dimensions and unit support
- Supports unit, currency, date, and time calculations
- Offers custom recursive functions through web and command-line interfaces
- Where it doesn't
- Does not support complex numbers or vector and matrix operations
- Does not provide equation solving
- Its programming-language features may be more than a basic calculator user needs
Numbat fact sheet, pricing and score →
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