Math calculators and tools
Percentages, fractions, algebra, geometry and statistics. 36 tools.
Percentages
Percent of a number, increase, decrease, change, difference and error.
Percentage CalculatorFind X% of a number, what percent one number is of another, or the whole from a part.Percentage Increase CalculatorFind the percentage increase between two values, or add a percentage to a number.Percentage Decrease CalculatorFind the percentage drop between two values, or take a percentage off a number.Percentage Change CalculatorSigned percentage change from a starting value to a new value, up or down.Percentage Difference CalculatorHow different two values are, as a percentage of their average — order doesn't matter.Percentage Error CalculatorPercentage error between a measured value and the true value, with signed and absolute error.
Fractions and ratios
Fraction CalculatorAdd, subtract, multiply and divide fractions and mixed numbers, simplified automatically.Fraction to Decimal CalculatorConvert a fraction to a decimal, including the repeating part.Decimal to Fraction CalculatorTurn a decimal — even a repeating one — into an exact fraction in lowest terms.Fraction to Percentage CalculatorConvert a fraction to a percentage and a decimal.Ratio CalculatorSimplify a ratio to lowest terms, or split an amount in a given ratio.Proportion CalculatorSolve for the missing value in direct or inverse proportion (A/B = C/D).
Algebra and powers
Scientific CalculatorType a full expression with brackets, powers, trigonometry, logs and factorials, in degrees or radians.Quadratic Equation SolverSolve ax² + bx + c = 0: discriminant, real or complex roots, vertex and factored form.Linear Equation SolverSolve ax + b = c, or two equations in x and y, with steps and a check.Exponent CalculatorRaise a number to any power, with exact integer results, fractions and scientific notation.Square Root CalculatorFind square, cube or nth roots, with simplified radical form and a perfect-power check.Logarithm CalculatorCalculate log of any base, plus ln, log₁₀ and log₂, or reverse it with an antilog.
Geometry
Pythagorean Theorem CalculatorFind the hypotenuse or a missing leg of a right triangle, plus its area, perimeter and angles.Triangle CalculatorSolve a triangle from three sides, two sides and an angle, or two angles and a side.Circle CalculatorFind the area, circumference, radius and diameter of a circle from any one of them.Area and Volume CalculatorArea, perimeter, volume and surface area for rectangles, trapezoids, cubes, cylinders, cones and spheres.
Averages, statistics and probability
Average CalculatorMean, median, mode, range, sum and count for a list of numbers.Weighted Average CalculatorAverage values that count for different amounts, such as graded assignments.Standard Deviation CalculatorStandard deviation and variance of a list of numbers, sample or population, with the working.Permutation and Combination CalculatornPr and nCr, with and without repetition, calculated exactly for large values.Probability CalculatorSingle events, two events (independent or exclusive) and repeated trials (binomial).
Number theory
HCF and LCM CalculatorHighest common factor (GCD) and lowest common multiple of two or more numbers, with prime factors.Prime Number CheckerCheck whether a number is prime, with its smallest factor and the previous and next primes.Prime Factorization CalculatorBreak a number into prime factors, with exponent form, divisor count and sum of divisors.Divisibility CheckerTest whether a number divides evenly by 2 to 12 or your own divisor, with the rule used.Remainder CalculatorDivide whole numbers to get the quotient and remainder, including how negatives behave.
Shopping, speed and work
Profit and Loss CalculatorProfit or loss and its percentage from cost and selling price, or find either price.Discount CalculatorSale price after one or two discounts and tax, or the discount percentage from two prices.Speed, Time and Distance CalculatorFind speed, time or distance when you know the other two, in your choice of units.Time and Work CalculatorHow long a job takes when several workers share it, or one worker's missing time.
About these math tools
These are the calculations people reach for most often — what is 15% of 240, how much did a price change, what do three fractions add up to. Each tool gives the answer first and then the steps behind it, so you can check the result or copy the method into your own homework or spreadsheet.
Percentages have the most pages because the same word hides different questions: a percentage of a number, a change between two numbers and a difference between two numbers each use a different formula. The tools below keep them separate on purpose.