📐 105 Calculators · 13 Topics · Updated April 2026
Math Calculators
Free math calculators for percentages, geometry, statistics, algebra, and arithmetic. Step-by-step formulas for students, professionals, and everyday problem-solving.
From quick percentage calculations to standard deviation and the quadratic formula, these math calculators handle the computations so you can focus on understanding the results. Every calculator shows the formula used, making them useful as both tools and learning aids.
Most Popular
Percentage Calculator
Calculate what percentage one number is of another, or find a percentage of any number.
Percentage Change Calculator
Calculate the percentage increase or decrease between two values.
Area of a Circle Calculator
Calculate the area, circumference, and diameter of a circle from its radius.
Pythagorean Theorem Calculator
Find the missing side of a right triangle using the Pythagorean theorem (a² + b² = c²).
Standard Deviation Calculator
Calculate mean, variance, and standard deviation for a set of numbers.
Quadratic Formula Calculator
Solve quadratic equations (ax² + bx + c = 0) using the quadratic formula.
Browse by Topic
Geometry
31 calculatorsFind areas, volumes, circumferences, and surface areas for circles, triangles, rectangles, cylinders, spheres, and cones. All standard geometric formulas.
Area of a Circle Calculator
Calculate the area, circumference, and diameter of a circle from its radius.
Area of a Triangle Calculator
Calculate the area of a triangle using base and height, or three sides (Heron's formula).
Circle Circumference Calculator
Calculate the circumference of a circle from radius or diameter.
Cone Volume Calculator
Calculate the volume and surface area of a cone from radius and height.
Cylinder Volume Calculator
Calculate the volume and surface area of a cylinder from radius and height.
Pythagorean Theorem Calculator
Find the missing side of a right triangle using the Pythagorean theorem (a² + b² = c²).
Rectangle Area Calculator
Calculate the area and perimeter of a rectangle from length and width.
Sphere Volume Calculator
Calculate the volume and surface area of a sphere from its radius.
Area of Rectangle Calculator
Calculate area, perimeter, and diagonal of a rectangle.
Area of Trapezoid Calculator
Calculate the area of a trapezoid from parallel sides and height.
Arc Length Calculator
Arc length from radius and angle.
Circle Sector Area Calculator
Pie-slice area from radius and central angle.
Ellipse Area and Perimeter
Area and Ramanujan-perimeter of an ellipse.
Regular Polygon Area Calculator
Area of any regular n-gon.
Tetrahedron Volume Calculator
Volume of a regular tetrahedron.
Pyramid Volume Calculator
Volume of a square pyramid.
Torus Volume Calculator
Volume of a donut shape.
Rectangular Prism Volume
Box volume, surface area, and diagonal.
Cube Surface Area Calculator
Surface area, volume, and diagonal of a cube.
Rhombus Area Calculator
Area from diagonal lengths.
Parallelogram Area Calculator
Area from base and height.
Hexagon Area Calculator
Area of a regular hexagon.
Right Triangle Calculator
Solve a right triangle from two sides.
Midpoint Calculator
Midpoint between two points.
Distance Between Points Calculator
Euclidean distance in 2D.
Triangle Area (Heron) Calculator
Area from three side lengths.
Sphere Volume Calculator
Volume of a sphere.
Sphere Surface Area Calculator
Surface area of a sphere.
Cone Volume Calculator
Volume of a cone.
Cube Volume Calculator
Volume of a cube.
Rectangle Perimeter Calculator
Perimeter of a rectangle.
Statistics
20 calculatorsCalculate mean, median, mode, standard deviation, variance, and averages. Essential for data analysis and research.
Average Calculator
Calculate the average (mean) of a set of numbers. Also shows sum and count.
Mean, Median, Mode Calculator
Calculate the mean (average), median (middle), and mode (most common) of a data set.
Probability Calculator
Calculate the probability of events, combinations, and permutations.
Standard Deviation Calculator
Calculate mean, variance, and standard deviation for a set of numbers.
Average Calculator
Calculate mean, median, mode, and range of a data set.
Normal Distribution Calculator
P(Z) from mean and std deviation.
Z-Score Calculator
Standard score from a value and distribution.
Confidence Interval Calculator
95% CI for a sample mean.
Margin of Error Calculator
Poll MOE from sample size.
Sample Size Calculator
Required n for a survey at 95% confidence.
Chi-Square Calculator
Goodness-of-fit chi-square test.
T-Test Calculator
Independent two-sample t-statistic.
Correlation Coefficient Calculator
Pearson r from two datasets.
Linear Regression Calculator
y = mx + b best-fit line.
Factorial Calculator
n! for positive integers.
Combination (nCr) Calculator
Count of r-subsets of n.
Permutation (nPr) Calculator
Ordered r-arrangements of n.
Arithmetic Mean Calculator
Mean of 10 numbers.
Geometric Mean Calculator
nth root of a product of n values.
Weighted Average Calculator
Weighted mean of three values.
Arithmetic
5 calculatorsWork with fractions, exponents, logarithms, scientific notation, ratios, and random numbers.
Exponent Calculator
Calculate the result of any number raised to any power (x^n).
Fraction Calculator
Add, subtract, multiply, and divide fractions with step-by-step solutions.
Logarithm Calculator
Calculate logarithms in any base, log, ln, log2, and custom bases.
Ratio Calculator
Simplify ratios, find equivalent ratios, and solve proportion problems.
Scientific Notation Calculator
Convert numbers to and from scientific notation and perform calculations.
Percentages
5 calculatorsCalculate percentages of numbers, percentage changes between values, percentage differences, and discount amounts. The most common math operations in everyday life.
Percentage Calculator
Calculate what percentage one number is of another, or find a percentage of any number.
Percentage Change Calculator
Calculate the percentage increase or decrease between two values.
Percentage Difference Calculator
Calculate the percentage difference between two values using their average as the base.
Percentage of a Number
Find what a specific percentage of any number is. Calculate X% of Y instantly.
Percentage Off Calculator
Calculate the sale price after a percentage discount. See how much you save.
Algebra
10 calculatorsSolve quadratic equations with the quadratic formula and calculate slopes of lines from two points.
Quadratic Formula Calculator
Solve quadratic equations (ax² + bx + c = 0) using the quadratic formula.
Slope Calculator
Calculate the slope of a line from two points and get the equation of the line.
Quadratic Equation Solver
Solve ax² + bx + c = 0 using the quadratic formula.
Slope Calculator
Calculate slope, y-intercept, and distance between two points.
Decimal to Fraction Converter
Approximate a decimal as a simple fraction.
Percent Change Calculator
Percent change between two values.
Percent Decrease Calculator
Apply a percent decrease.
Percent Of Calculator
What is X% of Y.
Reverse Percentage Calculator
Original value before a percent change.
Quadratic Formula Calculator
Roots of ax² + bx + c.
Tools
1 calculatorGenerate random numbers within specified ranges for various applications.
Fractions
1 calculatorNumber Theory
9 calculatorsPrime Factorization Calculator
Find prime factors of any integer.
Fibonacci Number Calculator
Get F(n) and the golden-ratio approximation.
GCD Calculator
Greatest common divisor of two integers.
LCM Calculator
Least common multiple of two integers.
Modulo Calculator
Remainder a mod n.
Binary → Decimal Converter
Convert binary integers to decimal.
Decimal → Binary Converter
Convert decimals to binary.
Hex → Decimal Converter
Convert hex to decimal.
Roman Numeral Converter
Convert between Roman numerals and integers.
Basic Math
8 calculatorsRatio Calculator
Solve ratio proportions: if A:B = C:?
Square Root Calculator
Principal square root with steps.
Cube Root Calculator
Cube root of any real number.
Nth Root Calculator
Any nth root.
Percent of a Number Calculator
X% of Y.
Percent Off Calculator
Sale price after X% off.
Percent Increase Calculator
Percent change from A to B.
Rule of 72 Calculator
Years to double an investment.
Linear Algebra
4 calculatorsProbability
2 calculatorsTrigonometry
7 calculatorsLaw of Cosines Calculator
Solve a triangle given SAS or SSS.
Law of Sines Calculator
Solve a triangle given ASA or AAS.
Sine Calculator
sin(θ) in degrees or radians.
Cosine Calculator
cos(θ) in degrees or radians.
Tangent Calculator
tan(θ) with asymptote warnings.
Inverse Trig Calculator
arcsin, arccos, arctan.
Radian ↔ Degree Converter
Angle unit conversion.
Frequently Asked Questions
How do I calculate a percentage?
There are three basic percentage operations: (1) What is X% of Y? Multiply Y × X/100. (2) X is what percent of Y? Divide X/Y × 100. (3) X is Y% of what? Divide X by Y/100. Our percentage calculator handles all three.
What is the Pythagorean theorem?
For any right triangle: a² + b² = c², where c is the hypotenuse (the longest side, opposite the right angle). Enter any two sides to find the third. Common right triangles include 3-4-5, 5-12-13, and 8-15-17.
When should I use standard deviation vs. variance?
Standard deviation and variance both measure data spread, but standard deviation is in the same units as your data, making it more intuitive. Variance (standard deviation squared) is used more in statistical formulas and tests. For reporting and comparison, standard deviation is usually preferred.