Free Math Calculators

These calculators handle the math people look up most: taking a percentage of a number, adding fractions, working out a final grade or GPA, and finding the area or volume of a shape. For algebra and statistics homework there are solvers for the quadratic formula, slope, standard deviation, probability, and combinations and permutations.

Many of them show their work instead of just the answer. The fraction calculator simplifies step by step, the percentage calculator shows the formula it used, and the quadratic solver checks the discriminant before giving real or complex roots. Big numbers stay exact: the factorial and combinations tools use whole-number arithmetic with no rounding, so 100! prints all 158 digits.

Answers are worked out in your browser, and the numbers you enter are not sent to our servers.

26 free tools in this category. All run in your browser with no signup.

Percentages, fractions and everyday math

Start with the online calculator, which has keyboard support and a history, or go straight to percentages, fractions, aspect ratios and splitting a restaurant bill.

Scientific CalculatorOnline scientific calculator with sin, cos, tan, log, ln, powers, roots and factorials, degrees or radians, a phone-style percent key and answer history.Percentage CalculatorFind X% of Y, what percent X is of Y, a missing total, percent change, or add and subtract a percent, with the formula and your numbers worked through.Fraction CalculatorAdd, subtract, multiply and divide fractions and mixed numbers with exact step-by-step working, a simplified answer, a mixed number and a decimal.Aspect Ratio CalculatorFind the aspect ratio of any width and height, or lock a ratio like 16:9 and type one side to get the other.Tip SplitterSplit a restaurant check by who ordered what, share items between people, and add tax and tip, with equal and custom-share modes.

Grade and GPA calculators

Work out a weighted course grade, the score you need on the final exam to reach a target grade, or your semester and cumulative GPA from credits and letter grades.

GPA CalculatorCalculate unweighted and weighted GPA from courses, credits and letter grades on the 4.0 scale, with Honors and AP bonuses and a cumulative GPA option.Grade CalculatorCalculate your weighted course grade with letter grade and 4.0 GPA points, and find the score you need on the final exam to reach a target grade.

Geometry: area, volume and triangles

Find a missing side of a right triangle, the area of a circle, triangle or rectangle, or the volume and surface area of a cylinder, sphere or box, whether it is for homework or for sizing a real tank or planter.

Pythagorean Theorem CalculatorSolve a² + b² = c² for the hypotenuse or a missing leg, or check if three sides form a right triangle.Triangle Area CalculatorFind a triangle's area from base and height, from three sides with Heron's formula, or from two sides and the included angle, with the working shown.Circle Area and Circumference CalculatorFind a circle's area, circumference, diameter and radius from any one value, with answers in terms of pi plus optional units and pi values.Rectangle Area CalculatorFind the area, perimeter and diagonal of a rectangle from its length and width, or solve for a missing side, with square feet, meters and acres.Cylinder Volume CalculatorFind a cylinder's volume in liters, US gallons and cubic feet from its radius or diameter and height, plus lateral and total surface area for tanks and pipes.Sphere Volume CalculatorFind the volume and surface area of a sphere from its radius, diameter or circumference, with liters, US gallons and hemisphere volume.Cube and Box Volume CalculatorFind the volume of a cube or rectangular box in cubic feet, cubic yards, liters and gallons, plus surface area and space diagonal.

Statistics and probability

Get the mean, median, mode, variance and standard deviation of a data set, probabilities for dice, coins and combined events, and exact counts of combinations and permutations.

Standard Deviation CalculatorPaste a data set to get sample and population standard deviation, variance, mean, median, mode and range, with step-by-step working and a distribution plot.Average CalculatorFind the average of any list of numbers, plus the median, mode, range, sum, min and max.Probability CalculatorCalculate the probability of one event, two events (AND, OR), conditional probability, dice sums and coin flips, as a percent, fraction and odds.Permutation and Combination CalculatorCalculate permutations P(n,r) and combinations C(n,r), with and without repetition, as exact whole numbers for n and r up to 5,000.Factorial CalculatorCalculate the exact factorial n!

Algebra and coordinate geometry

Solve quadratic equations, find the slope, midpoint or distance between two points, and add, multiply or invert matrices up to 5×5.

Quadratic Equation SolverSolve ax² + bx + c = 0 with the quadratic formula: discriminant, exact and decimal roots (real or complex), factored form, vertex and steps.Slope CalculatorFind the slope between two points as a fraction and decimal, with the line equation, angle of inclination, percent grade and rise over run steps.Midpoint CalculatorFind the midpoint of two points in 2D or 3D, or work out a missing endpoint from the midpoint, with every step shown and exact fractions.Distance Formula CalculatorFind the distance between two points in 2D or 3D with the distance formula.Matrix CalculatorAdd, subtract and multiply matrices, or find the determinant, inverse, transpose, rank and RREF of a matrix up to 10x10 with exact fraction answers.

Primes and scientific notation

Check whether a number is prime and see its prime factors and divisors, or convert between standard form, scientific notation, E-notation and SI prefixes.

Prime Number CheckerCheck whether a number is prime and get its prime factorization, divisors, and the previous and next prime.Scientific Notation ConverterConvert any number to scientific, engineering and E-notation with SI prefixes, or add, subtract, multiply and divide numbers in scientific notation.

Frequently asked questions

How do I calculate a percentage of a number?

Divide the percentage by 100 and multiply: 20% of 150 is 0.20 × 150 = 30. To find what percent one number is of another, divide the part by the whole and multiply by 100, so 30 out of 150 is 20%. The percentage calculator does both, plus percentage change between two numbers.

What is the difference between mean, median and mode?

The mean is the total of the values divided by how many there are. The median is the middle value once the values are sorted (or the average of the two middle values). The mode is the value that appears most often. For 2, 3, 3 and 8, the mean is 4, the median is 3 and the mode is 3. The average calculator shows all three at once.

When do you use combinations instead of permutations?

Use combinations when order does not matter, such as choosing 3 people from 10 for a committee: C(10,3) = 120. Use permutations when order matters, such as giving gold, silver and bronze to 3 of 10 runners: P(10,3) = 720. The combinations and permutations calculator handles both, with or without repetition.

How do I find the hypotenuse of a right triangle?

Square the two shorter sides, add them and take the square root: c = √(a² + b²). For sides of 3 and 4, c = √25 = 5. The Pythagorean theorem calculator also finds a missing shorter side, the angles and the area.

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