8 Best Free Open Source Calculator Software For Windows

Here is a list of best free open source calculator software for Windows. What distinguishes these calculators from the calculators listed here is the fact that these are free and open source calculators. You can find the source code of these calculators from their official websites. The source code can be downloaded, studied, and manipulated by the interested users.

You can perform simple as well as complex calculations using these software. These let you solve different kinds of mathematical problems including AlgebraCalculusCombinatoricsComplex NumbersData SetsDate & Time, Exponents & LogarithmsGeometryLogicalMatrices & VectorsNumber TheoryStatisticsStep FunctionsTrigonometry, etc. In addition, you can also perform calculations related to graphs, physics, economics, probabilities, etc. Some of these also provide some constants to add in the input expression. A few of these also provide a formula book containing some generic formulae to use directly in your calculations. You can also record an expression as a macro to quickly use later. Apart from these features, you can view calculation history, import expressions from CSV file, save results, etc.

My Favorite Open Source Calculator Software For Windows:

Qalculate is my favorite open source calculator for Windows. It lets you solve a wide number of problems in different approximation and fractional modes.

You may also like some best free Open Source Billing Software, Open Source Budgeting Software, and Math Equation Editor Software for Windows.


Qalculate is a free open source calculator software for Windows. It is quite an advanced calculator with various approximation modes (Always Exact, Interval Arithmetic, Try Exact, Approximate) and fractional modes (Decimal Rationals, Exact Rationals, Fraction, Combined). You can also select number base, numerical display, unit display, assumptions, algebraic mode, precision, decimal, RPN mode, angle unit, etc. to perform calculations. Just type an expression and hit enter to get respective results. You can also view calculation history on its main interface which can be copied to the clipboard. The good part is that it lets you import expression from CSV files for calculation purpose and later export results to another CSV file.

It supports different kinds of calculations which include Algebra (linear equation, summation, differential equation, etc.), Calculus (integrate, differentiate, limit, etc.), Combinatorics (combinations, factorial, double factorial, permutations, derangements, etc.), Complex Numbers, Data Sets, Date & Time, and Exponents & Logarithms. There are many more calculations which can be performed using this open source calculator. These include Economics (microeconomics, compound, dollar decimal, dollar fraction, interest rate, treasury bill price, etc.), Geometry (circle, conde, cube, cylinder, sphere, square, etc.), Logical, Matrices & Vectors, Number Theory, Statistics (mean, moments, random numbers, distribution, etc.), Step Functions, Trigonometry, etc. It provides some additional utilities which you can use, such as Replace, Concatenate String, Interval, Function, RPN Stack Register, RPN Stack Vector, Process Matrix Elements, etc. A separate Conversion tab is provided to carry out various unit conversions. From its Variables menu, you can add various variables including physical constants, date & time, basic constants, large numbers, small numbers, etc. Also, you can select and add a unit for a particular calculation such as angular acceleration, currency, electric charge, electric current, pressure, surface tension, and many more.

In general, it is one of the best solutions to the students or general users who are looking for a free and open source calculator software.


SpeedCrunch is a nice free open source calculator software for Windows. It lets you perform basic and scientific calculations. It comes with a formula book with various formulae related to different functions including Algebra, Geometry, Unit Conversions, Electronics, and Radio Frequency. You can directly select a formula, fill in values, and get the respective results. If there is a mistake in the input expression, it will display the error. You can also view constants and respective values, functions, variables, etc. It lets you add user functions as well. Apart from these basic features, you get some other useful options which are:

  • It lets you view the history of performed calculations.
  • You can export performed calculations as TXT or HTML file.
  • It lets you customize result format, input format, and angle unit.
  • You can customize software behavior, display settings, and language too.

Precise Calculator

Precise Calculator is a free, portable, and open source calculator for Windows. Using it, you can perform basic as well as scientific calculations. You can use some generic constant values directly in your calculations from its Constants menu. It lets you set arbitrary precision value and select units to perform calculations. Also, you can select number base (binary, decimal, hexadecimal), angle unit, and result format (normal, scientific, engineering, fix).

It lets you create macros for specific functions to use them later. You can also use some inbuilt macros including prime numbers, cubic equations, quadratic equations, divisors, various plane, etc. The history of calculations can also be retrieved any time. The results can be saved in a text file. There are various program settings that you can configure including log file creation, font and color customization, interface language selection, etc.


Xcas is the next open source calculator software for Windows. It can be used to perform a variety of calculations which include simple arithmetic calculations, trigonometry functions, factorization, calculus (integration, derivatives, Laplace transform, etc.), linear algebra (create matrix, transpose, image, kernel, etc.), equations (linear equation, differential equation, recurrence equation, etc.), and probability. It also lets you quickly perform graphs (curve, surface, sequence, trace, animation, etc.), geometry (points, lines, triangles, circles, polygons, solids, transformation, etc.), and physics (area, volume, length, energy, temperature, pressure, viscosity, etc.) related calculations. It provides some inbuilt commands in different categories to use in calculations, such as constants, permutations, intervals, complex, linear algebra, polynomials, etc.

As you perform calculations, you can view the calculation history for current session on its interface. You can print the results or save them in its native file formats for later use.

All in all, it is a good calculator software which comes with open source license. You can configure various properties in this software such as graph configuration, language, font, color, etc.


GraphCalc is one more open source calculator in this list. It lets you perform various calculations which include basic arithmetic operations, trigonometry problems, 2D graphing, conversion, etc. It provides a dedicated Equation Solver tool to solve a single variable algebraic equations. In addition, some generic calculations like area, surface area, volume, quadratic equations, etc. can directly be performed. For 2D graphing, you get analysis options like Find Area, Trace, Tangent Line, Distance Between Two Points, N-Slider, etc. You can copy, print, or export the graph to BMP image.

From its Options > Mode option, you can select Decimal Places, Output Format, Unit, Base, etc. You can save specific commands to a script file so that you can use it later. It lets you save output to an RTF file. The calculation history can be easily viewed from the interface.


Kalq is a simple open source calculator for Windows. It has a compact interface as you can see in above screenshot and it works in distraction free mode. After launching it, type or copy and paste expression you want to solve in the bar. As you type the expression, it displays respective results in real time. You can solve simple mathematical problems in it like fractions, multiply, square root, square, cube, inversion, etc.

On clicking the option highlighted in above screenshot, you can access various options like History, Bar Size, Formatting, Copy Answer, etc


TTCalc is another free open source calculator for Windows. It incorporates arithmetical functions, trigonometric functions, inverse trigonometric functions, hyperbolic functions, inverse hyperbolic functions, logical operators, logarithms, etc. for calculations. It lets you add custom variables and functions to use in calculations. The precision value can be set to small, medium, or high. From Display tab, you can set parameters like input base, output base, input decimal point, output decimal point, rounding, etc.


JCalc is another one of open source calculators for Windows. It is a portable calculator which needs to no installation and can be used on the go.

It is quite a simple calculator which lets you perform simple, binary, octal, and hexadecimal calculations, and solve simple equations. A keypad to enter an expression is provided in it. The history of added expressions is visible on the interface. You can also save the expression with the respective result in a separate file.

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