Tools

Math & Statistics Calculators

Most math calculators online give you a number and stop. The problem with that is that arithmetic is rarely where people go wrong — the mistake is upstream, in choosing sample standard deviation when the data is the whole population, or reading a z-score without knowing which tail the probability refers to.

So every tool here shows the formula it used and names the convention it followed. Where two conventions genuinely compete — n versus n−1, degrees versus radians, whether zero counts as a significant figure — both answers are given rather than one being silently picked for you.

All 25 math & statistics tools

Fractions, averages, spread, probability, geometry, and the algebra behind them.

FractionAdd, subtract, multiply, and divide fractions in lowest terms.Decimal to FractionExact fraction for any decimal, including repeating ones.Mean, Median, Mode & RangeEvery centre and spread statistic for a list of numbers.Standard DeviationSample and population deviation, variance, and standard error.Z-ScoreHow many deviations from the mean, and the probability that implies.Confidence IntervalThe margin of error around a sample mean at any confidence level.Sample SizeHow many responses a survey needs for a given margin of error.ProbabilityUnion, intersection, complement, and conditional probability.Permutations & CombinationsnPr and nCr, with exact answers well past the float limit.Factorialn! exactly, however many digits that turns out to be.Quadratic FormulaRoots, discriminant, and vertex for any quadratic equation.Slope & Line EquationSlope, intercept, distance, and midpoint from two points.ExponentPowers with negative and fractional exponents handled properly.Square RootSquare, cube, and nth roots, plus simplified radical form.LogarithmSolve for any of the three parts of log base b of x.RatioSimplify a ratio, solve A∶B = C∶D, or scale one to a total.GCF & LCMGreatest common factor and least common multiple for any list.Prime FactorizationBreak a number into its prime factors, in exponent form.Significant FiguresCount the significant figures in a number, or round to a count.Scientific NotationConvert to and from scientific notation without losing precision.Percent ErrorHow far an observed value sits from the expected one.Area of a ShapeArea for seven shapes, from rectangles to sectors.Volume of a SolidVolume for cubes, cylinders, spheres, cones, and pyramids.Triangle SolverSolve any triangle from SSS, SAS, ASA, or two right-angle sides.CircleRadius, diameter, circumference, and area from any one of them.

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