Free Online Calculators & Converters
Calculate percentages, convert units, estimate loan payments, and more with our free online math tools. Instant results with no signup required.
Percentage Calculator
Solve any percentage problem instantly. Calculate what X% of Y is, find percentage increase or decrease, or determine what percent one number is of another.
Use tool →Age Calculator
Enter your date of birth to see your exact age in years, months, and days. Also see days until your next birthday and the day of the week you were born.
Use tool →BMI Calculator
Enter your height and weight to calculate your Body Mass Index (BMI) and see where you fall on the standard BMI scale. Supports both metric and imperial units.
Use tool →Loan Payment Calculator
Estimate your monthly loan payment based on principal amount, interest rate, and loan term. See total interest paid and the full repayment breakdown.
Use tool →Compound Interest Calculator
See how your savings or investments grow over time with compound interest. Adjust principal, rate, compounding frequency, and contributions to plan your financial future.
Use tool →Tip Calculator
Calculate the right tip amount and split the bill evenly among any number of people. Choose from common tip percentages or enter a custom amount.
Use tool →Unit Converter
Convert between units of length, weight, temperature, volume, speed, area, and more. A universal converter for everyday and professional use.
Use tool →Length Converter
Convert between all common length units instantly. Supports meters, feet, inches, centimeters, millimeters, kilometers, miles, yards, and more.
Use tool →Weight Converter
Convert between kilograms, pounds, ounces, grams, milligrams, metric tons, and more. Instant, accurate weight conversions.
Use tool →Temperature Converter
Convert temperatures between Celsius, Fahrenheit, and Kelvin with a single input. See the conversion formulas and common reference points.
Use tool →Circle Area Calculator
Enter the radius of any circle and instantly compute its area using the standard πr² formula. Ideal for geometry homework, engineering, and design projects.
Use tool →Circle Circumference Calculator
Quickly determine the circumference of a circle by providing the radius. Uses the precise 2πr formula for accurate perimeter measurement.
Use tool →Triangle Area Calculator
Compute the area of any triangle by entering the base and height. Uses the standard ½ × base × height formula for fast, accurate results.
Use tool →Rectangle Area Calculator
Find the area of any rectangle by entering its length and width. Perfect for calculating room sizes, material quantities, and garden plots.
Use tool →Rectangle Perimeter Calculator
Enter the length and width to find the total perimeter of a rectangle. Great for planning fences, picture frames, and border materials.
Use tool →Sphere Volume Calculator
Determine the volume of any sphere by entering the radius. Uses the standard (4/3)πr³ formula for tanks, balls, and spherical containers.
Use tool →Sphere Surface Area Calculator
Calculate how much surface a sphere has by entering its radius. The 4πr² formula helps estimate material for coating, wrapping, or painting spherical objects.
Use tool →Cylinder Volume Calculator
Enter the radius and height of a cylinder to compute its volume. Uses πr²h — useful for sizing tanks, cans, pipes, and cylindrical containers.
Use tool →Cone Volume Calculator
Find the volume of any cone by entering its base radius and height. The (1/3)πr²h formula gives you the exact capacity for funnels, cones, and more.
Use tool →Trapezoid Area Calculator
Compute the area of a trapezoid by entering both parallel sides and the height. Applies the standard ½(a + b) × h formula for quick results.
Use tool →Parallelogram Area Calculator
Enter the base and perpendicular height to calculate the area of any parallelogram. Simple, fast, and accurate for all parallelogram shapes.
Use tool →Ellipse Area Calculator
Enter the semi-major and semi-minor axes to compute the area of an ellipse using π × a × b. Useful for oval designs, tracks, and engineering.
Use tool →Cube Volume Calculator
Find the volume of a cube by entering the side length. Computes s³ instantly — ideal for packaging, storage, and cubic capacity planning.
Use tool →Pythagorean Theorem Calculator
Enter two sides of a right triangle to find the hypotenuse using a² + b² = c². Essential for construction, navigation, and geometry problems.
Use tool →Diagonal Calculator
Find the diagonal of any rectangle by entering its length and width. Applies √(l² + w²) for screen sizes, room diagonals, and construction layouts.
Use tool →GCD Calculator
Enter two numbers to find their greatest common divisor (GCD), also known as the highest common factor (HCF). Essential for simplifying fractions.
Use tool →LCM Calculator
Enter two numbers to find their least common multiple (LCM). Useful for adding fractions with different denominators and solving scheduling problems.
Use tool →Factorial Calculator
Enter a non-negative integer to calculate its factorial (n!). Handles values up to 170 for combinatorics, probability, and permutation problems.
Use tool →Fibonacci Calculator
Enter a position to get the corresponding Fibonacci number. The Fibonacci sequence appears in nature, art, algorithms, and financial analysis.
Use tool →Prime Number Checker
Enter a number to determine whether it is prime. Also displays the nearest prime numbers above and below your input for quick reference.
Use tool →Square Root Calculator
Enter a number to compute its square root. Supports decimals and provides high-precision results for math, science, and engineering work.
Use tool →Cube Root Calculator
Enter any number to find its cube root. Unlike square roots, cube roots work with negative numbers too — perfect for algebra and volume problems.
Use tool →Exponent Calculator
Raise any base to any power — including decimals, fractions, and negative exponents. A versatile tool for algebra, physics, and financial formulas.
Use tool →Logarithm Calculator
Compute logarithms for any positive number with any base. Defaults to base 10 but supports natural log (e), base 2, and any custom base.
Use tool →Modulo Calculator
Compute the remainder when dividing one number by another. The modulo operation is fundamental in programming, cryptography, and clock arithmetic.
Use tool →Average Calculator
Enter a list of comma-separated numbers to compute their arithmetic mean. Works with any count of values — from two to thousands.
Use tool →Quadratic Equation Solver
Enter coefficients a, b, and c to solve ax² + bx + c = 0. Displays both roots, the discriminant, and whether roots are real or complex.
Use tool →Ratio Calculator
Solve proportions by entering three known values to find the fourth. If A:B = C:D, enter A, B, and C to calculate D automatically.
Use tool →Scientific Notation Converter
Convert any number into scientific notation or back to standard form. Handles extremely large and small values for science and engineering.
Use tool →Combination Calculator
Find how many ways you can choose r items from n items when order does not matter. Uses the nCr = n! / (r!(n-r)!) formula.
Use tool →Permutation Calculator
Determine how many ways you can arrange r items from n items when order matters. Uses nPr = n! / (n-r)! for rankings and seating charts.
Use tool →Electricity Cost Calculator
Estimate the cost of running an electrical device based on its wattage, usage hours, and your electricity rate.
Use tool →Ohm's Law Calculator
Enter any two of voltage (V), current (I), and resistance (R) to calculate the third using Ohm's Law.
Use tool →Percentage Increase Calculator
Enter an original value and a new value to calculate the percentage increase between them.
Use tool →Percentage Decrease Calculator
Enter an original value and a new value to calculate the percentage decrease between them.
Use tool →Mean Calculator
Enter a list of numbers to calculate the arithmetic mean. Supports any number of values.
Use tool →Median Calculator
Enter numbers to find the median — the middle value when sorted. For even counts, it's the average of the two middle values.
Use tool →Standard Deviation Calculator
Enter numbers to calculate the standard deviation, which measures how spread out the values are from the mean.
Use tool →Fuel Cost Calculator
Estimate the fuel cost of a trip by entering the distance, your vehicle's fuel economy, and the price per gallon/liter.
Use tool →Paint Calculator
Enter room dimensions to estimate how many gallons of paint you need. Accounts for doors and windows.
Use tool →Concrete Calculator
Calculate the volume of concrete needed for slabs, footings, and columns based on dimensions.
Use tool →Learn More
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