20 CALCULATORS
← All toolsMaths & statistics calculators
Calculators for school, university and work maths: solve triangles and quadratic equations, find slopes, logarithms, powers and roots, factorise numbers, round correctly and convert to scientific notation.
For statistics there are z-scores and percentiles, confidence intervals, survey sample sizes, probabilities and counting with permutations and combinations. Every page shows the formula and a worked example computed by the same engine, and results are checked against an independent reference implementation.
GeometryTriangle calculator (three sides) Enter three side lengths to get a triangle's area, perimeter, all three angles, its type and the radii of its inscribed and circumscribed circles.GeometryRight triangle and Pythagorean theorem calculator Find the hypotenuse of a right triangle from its two shorter sides with Pythagoras's theorem, plus its area, perimeter, angles and height.GeometryCircle calculator: area, circumference and diameter Enter a circle's radius, diameter, circumference or area to get all four measurements, calculated with the full precision of pi.AlgebraQuadratic equation solver Solve ax² + bx + c = 0 with the quadratic formula. Shows real or complex roots, the discriminant and the vertex of the parabola.AlgebraSlope calculator: slope, distance and midpoint Enter two points to find the slope of the line through them, its equation, the distance between the points, the midpoint and the angle.AlgebraLogarithm calculator (any base) Calculate the logarithm of a number in any base, along with its natural logarithm (ln), common logarithm (log₁₀) and binary logarithm (log₂).AlgebraExponent calculator (powers) Raise a number to any power, including negative and fractional exponents, and see the reciprocal and square root of the result.AlgebraRoot calculator: square, cube and nth roots Find the square root, cube root or any nth root of a number, including odd roots of negative numbers.Number theoryGCF and LCM calculator Find the greatest common factor (highest common factor) and least common multiple of two or three whole numbers, calculated exactly.Number theoryPrime factorisation calculator Break a whole number into its prime factors, check whether it is prime, and count and add up all of its divisors.ArithmeticRounding calculator Round a number to any number of decimal places, or to tens, hundreds and thousands, using half-up, banker's (half-even), up, down or truncation.ArithmeticScientific notation converter Convert any number to scientific, E and engineering notation with the number of significant figures you choose.ArithmeticPercent error calculator Compare a measured value with an accepted (true) value to get the percent error, absolute error and signed error.ArithmeticRatio calculator (A : B = C : D) Solve a proportion A : B = C : D for the missing value, simplify a ratio to its lowest terms and see the scale factor.ProbabilityPermutation and combination calculator (nPr, nCr) Count the ways to choose r items from n, with and without order and with and without repetition: nCr, nPr, nʳ and multisets.StatisticsZ-score calculator with percentile Convert a value to a z-score from the mean and standard deviation, and get its percentile and the tail areas of the normal distribution.ProbabilityProbability calculator for two independent events Combine the probabilities of two independent events: both happening, at least one, exactly one, neither, and each not happening.StatisticsSample size calculator for surveys Find how many responses a survey needs for a chosen confidence level and margin of error, with an optional finite population correction.StatisticsConfidence interval calculator for a mean Estimate a confidence interval for a population mean from the sample mean, standard deviation and sample size, with the margin of error.ScienceHalf-life calculator Work out how much of a substance remains after a given time from its half-life, plus the decay constant and mean lifetime.