How many math tools are there?

40: Percentage Calculator, Average Calculator, Mean, Median, Mode, Range Calculator, Standard Deviation Calculator, Statistics Calculator, Random Number Generator, Ratio Calculator, Percent Error Calculator and more. Each one shows the formula or rule it uses, so you can check the answer rather than trusting it.

Which math tool should I use first?

Percentage Calculator is the most used on the shelf: every common percentage question in one place. Every tool works the same way, with inputs at the top and the working underneath the answer.

Is it free, and is my data stored?

Free and private. The calculation runs in your browser, so figures never leave your device, there is no account, and no calculation is logged.

Mondo Knows Tools

Free Math Calculators for Percentages, Statistics, Geometry & More

From a quick percentage to a full standard deviation, these free maths calculators do the working so you can get on with it. Every tool shows the formula it uses, so the answer is something you can trust and learn from.

40 free tools on this shelf, all running in your browser

Area CalculatorArea of the common shapes.Average CalculatorMean, median, mode and range of any list.Big Number CalculatorMultiply or add very large integers exactly.Binary CalculatorConvert between binary and decimal.Circle CalculatorRadius, diameter, circumference and area together.Confidence Interval CalculatorRange that likely contains the true mean.Distance CalculatorStraight-line distance between two points.Equation SolverLinear, quadratic and two-variable systems, solved step by step.Exponent CalculatorPowers and roots, including fractional exponents.Factor CalculatorAll divisors of a number and its prime factors.Fraction CalculatorAdd, subtract, multiply and divide fractions.Greatest Common Factor CalculatorThe largest number that divides a list exactly.Half-Life CalculatorRadioactive decay, or anything that halves.Hex CalculatorConvert between hexadecimal and decimal.Least Common Multiple CalculatorThe smallest number a list all divides into.Log CalculatorLogarithms in any base, natural and common.Matrix CalculatorMultiply, add, invert and take determinants of matrices you type in.Mean, Median, Mode, Range CalculatorThe four classic summaries, side by side.Number Sequence CalculatorFind the next terms of an arithmetic or geometric sequence.Percent Error CalculatorHow far an estimate sits from the true value.Percentage CalculatorEvery common percentage question in one place.Permutation and Combination CalculatorWays to arrange or choose from a set.Prime Number CheckerTest a number, factor it, or list the primes in a range.Probability CalculatorTwo independent events, together or either.Pythagorean Theorem CalculatorSolve a right triangle's missing side.Quadratic Formula CalculatorRoots of ax^2 + bx + c = 0, including complex ones.Random Number GeneratorFair random numbers in any range.Ratio CalculatorSolve a proportion and simplify ratios.Right Triangle CalculatorEvery side and angle of a right triangle.Root CalculatorSquare roots, cube roots and any nth root.Rounding CalculatorRound to any precision, or to whole numbers.Sample Size CalculatorHow many responses a survey needs.Scientific Notation CalculatorConvert to and from scientific notation.Slope CalculatorSlope, line equation and angle between two points.Standard Deviation CalculatorSpread of a data set, population and sample.Statistics CalculatorA full summary of a data set in one pass.Surface Area CalculatorSurface area of common 3D shapes.Triangle CalculatorArea and perimeter from three sides.Volume CalculatorVolume of the common solids.Z-Score CalculatorHow many standard deviations a value sits from the mean.

Questions people ask

How many math tools are there?: 40: Percentage Calculator, Average Calculator, Mean, Median, Mode, Range Calculator, Standard Deviation Calculator, Statistics Calculator, Random Number Generator, Ratio Calculator, Percent Error Calculator and more. Each one shows the formula or rule it uses, so you can check the answer rather than trusting it.
Which math tool should I use first?: Percentage Calculator is the most used on the shelf: every common percentage question in one place. Every tool works the same way, with inputs at the top and the working underneath the answer.
Is it free, and is my data stored?: Free and private. The calculation runs in your browser, so figures never leave your device, there is no account, and no calculation is logged.