General Calculator Including Rule of Three is a free on line service (nothing to download and install), that will let you perform various mathematical operations and measure conversions.

Microsoft Mathematics provides a calculator that plots in 2D and 3D, featuring step-by-step equation solving, and useful tools to help students with math and science studies. With Microsoft Mathematics, students can learn to solve equations step-by-step while gaining a better understanding of fundamental concepts in pre-algebra, algebra, trigonometry, physics, chemistry, and calculus. Additional math tools help in evaluating triangles, converting from one system of units to another, and solving systems of equations.

Alt1 free scientific calculator features a modern minimal interface and it is fast, convenient and reliable, a program you should try if you are in search of a calculator.

Desktop Calculator gadget offers two modes, the simple, that most people need, and the scientific. It will let you customize its colors, select whether to use radians or degrees for trig calculations (Sin, Cos, Tan, aSin, aCos, aTan), change number display format.

Chasys Math Tools is a combination of free math utilities, the Chasys Math Calculator and the Chasys Math Matrix. The calculator supports graph-plotting and complex numbers. The matrix equation solver can handle systems of equations as large as 32 by 32.

WiseCalc is a complete mathematical text engine calculator. It supports evaluation of complex in-line mathematical expressions ; Evaluation of the Inverse, Prime Factors, and Decimal to Fraction automatically; Ability to use built-in or user defined constants in mathematical expressions; Standard, Engineering, Scientific, and Financial modes; All types of Trigonometric functions built in with Radian and Degree modes; Supports calculating and working with imaginary numbers in Rectangular, Polar, or Rectangular Sum modes; Evaluation of mathematical expressions in number bases 2 – 16 (decimal: 10 is the default), and more.

Fleye Graphing Calculator makes life easier for students and professionals in the sciences, by creating mathematical graphs for presentations (Physics, Differential Equations, Calculus).

SpeedCrunch Calculator lets you see clearly what you typed along with the result in a scrollable display. You can also paste your expression from the clipboard, and you can quickly copy the last calculation result to the clipboard. SpeedCrunch may even give the answer before you finish typing (calc-as-you-type)! This allows you to “fix” your expression if you think it is not what you wanted. If you want to recall again an expression that you typed before, you can access an expression history. Your expressions (the last 100 expressions) are saved between sessions. This means that you can still invoke those calculations you have done yesterday or last week.

Kalkules is a free scientific calculator, featuring an amount of non-traditional functions, which can be used particularly by high school or university students. It also offers a wide range of tools that make calculations easier and faster. Features: evaluating whole expressions ( ex: 5 + 10 / 3 ) * drawing function graphs * calculating with real complex or modulo numbers * calculating in four number systems: binary, octal, decimal, hexadecimal * calculating with fractions ( ex: 5 / 2 + 1 / 3 = 17 / 6 ) * calculating with polynomials * evaluation history * unlimited count of brackets in the expression * wide range of arithmetic goniometric and hyperbolic functions * using self-named variables ( ex: radius, volume, … ) * inserting some of the predefined constants + ability to define your own constants * inteligent percentage calculations, and more…

Calc 3D is a collection of mathematical tools for highschool and university. The calculator can do statistics, best fits, function plotting, integration. It handles vectors, matrices, complex numbers, coordinates, regular polygons and intersections. For objects ( like point, line, plane and sphere) distances and intersections are calculated. Cartesian, spherical and cylindrical coordinates can be transformed into each other. Cartesian plot, polar plot, parametric plot, best fit, fast fourier transformation, histogram, smooth, and more. It offers also Excel Import and Export.

Overlapping Polygons Calculator calculates the area of two (convex) polygons as well as their overlap. Convex means: any angle of the polygon is less than 180 degrees. The number of angles may vary from 3 to 12. Besides calculation of areas, the Polygon-Overlap-Calculator may be used to match geographic images such as maps and air photographs with coordinates on earth. All tables and procedures used for the calculations are neatly arranged in one unit. A step-by-step approach is used: procedures process tables to produce new tables on the way to the final result.

ESBCalc is a free Scientific Calculator featuring Infix Notation, Brackets, Scientific Functions (Trigonometric, Hyperbolic, Logarithmic – including Base 10, Base 2 & Natural – plus more), Memory, Paper Trail, Result History List, and more. ESBCalc includes support for Prefix functions so that to evaluate log (10) you can enter log 10 rather than 10 log, which is the default behaviour.

Precise Calculator offers the unique feature of arbitrary precision (from 1 to 9999999). Options: complex numbers * fractions * lists, vectors, matrices * history (shortcuts ctrl+up, ctrl+down) * commands if, goto, print, return * unlimited number of variables * frequently used formulas can be saved as macros * can be translated to other languages.

RedCrab is a well designed scientific calculator, featuring a full screen formula editor. Mathematical expressions are not typed in a typical command line, but can be entered in an editor window quite similar to a piece of paper. The calculator’s editor supports the entry of complex algebraic equations like fractions, square roots, exponents, etc., for technical and scientific applications.

Ideal Body Weight Calculator estimates your ideal body weight and the adjusted body weight according to your weight, height and gender. Just fill in the form fields and press the “Calculate” button.

Gretl can use data in TXT, SAS, CSV and SPSS formats. It lets you create distribution graphs, run non-parametric texts, make statistical tables, find p values, add personal observations, sort, etc. Among its estimators are maximum likelihood, least squares, GMM, single-equation and system methods.

Financial Calculator is specialized to help you achieve your goals easily and accurately, featuring 11 parts for 11 different financial calculations.

BMI calculator will help you discover your Body Mass Index (BMI). You can calculate your BMI using Metric or Standard systems of measurement. BMI Calculator will instantly interpret your BMI.

Weight Watchers Points Calculator gadget determines the Weight Watchers point value of any food, based on the calories, fat grams, and fiber grams per serving.

SunCalculator specializes in calculating Sunrise, Sunset and dawn times, astronomical twilight, nautical twilight and civil twilight for any date between 2099 and 1801.

Solve Elec analyzes electrical circuits, gets literal formulas and values for current intensities and voltages defined in the circuit, verifies circuit related equations, draws graphs, gets the equivalent circuit of displayed circuit, and more.