Math & Conversion
Solve percentages, fractions, averages, equations and conversions with free, easy math calculators. Each tool shows the formula and the steps, so you learn the method while you get the answer.
Popular in this category: Percentage Calculator, Percentage Increase Calculator, Percentage Change Calculator
Percentage Calculator
Solve any percentage problem - what is X% of Y and more
Percentage Increase Calculator
Calculate percent increase between two numbers
Percentage Change Calculator
Calculate the percent change and difference between values
Discount Calculator
Calculate the sale price and amount saved
Fraction Calculator
Add, subtract, multiply and divide fractions
Scientific Calculator
A full scientific calculator with trig, logs and more
GPA Calculator
Calculate your grade point average (weighted or unweighted)
Quadratic Formula Calculator
Solve quadratic equations with the quadratic formula
Average Calculator
Calculate the mean, median and mode of numbers
Ratio Calculator
Simplify, scale and solve ratios and proportions
Exponent Calculator
Raise numbers to any power
Square Root Calculator
Find the square root of any number
Standard Deviation Calculator
Calculate standard deviation, variance and mean
Density Calculator
Solve density, mass or volume with rho = mass / volume
Slope Calculator
Find the slope and equation of a line from two points
Distance Calculator
Calculate the distance between two coordinate points
Velocity Calculator
Find average velocity (v = d/t) and final velocity (v = u + at)
Area Calculator
Calculate the area of common shapes
Grade Calculator
Calculate your class grade and final exam score needed
Unit Converter
Convert length, weight, temperature, volume and more
Currency Converter
Convert between US dollars and 29 world currencies at ECB reference rates
GBP to USD Converter
Convert British pounds to US dollars at the current reference rate
Euro to Dollar Converter
Convert euros to US dollars at the current reference rate
USD to INR Converter
Convert US dollars to Indian rupees at the current reference rate
Mexican Peso to USD Converter
Convert Mexican pesos to US dollars at the current reference rate
USD to CAD Converter
Convert US dollars to Canadian dollars at the current reference rate
AUD to USD Converter
Convert Australian dollars to US dollars at the current reference rate
Yen to USD Converter
Convert Japanese yen to US dollars at the current reference rate
PHP to USD Converter
Convert Philippine pesos to US dollars at the current reference rate
GCF Calculator
Find the greatest common factor of numbers
LCM Calculator
Find the least common multiple of numbers
Scientific Notation Calculator
Convert numbers to and from scientific notation
Rounding Calculator
Round numbers to any decimal place
Significant Figures Calculator
Count and round to significant figures
Decimal to Fraction Calculator
Convert a decimal to a simplified fraction
Long Division Calculator
Solve long division with step-by-step work
Logarithm Calculator
Calculate log and natural log of any number
Pythagorean Theorem Calculator
Solve for any side of a right triangle
Triangle Calculator
Solve triangle sides, angles and area
Circle Calculator
Calculate area, circumference, radius and diameter
Volume Calculator
Calculate the volume of common 3D shapes
Perimeter Calculator
Calculate the perimeter of common shapes
Factorial Calculator
Calculate the factorial of a number (n!)
Permutation & Combination Calculator
Calculate nPr and nCr
Prime Factorization Calculator
Break a number into its prime factors
Binary Calculator
Convert and do math with binary numbers
Percent Error Calculator
Calculate percent error between values
Z-Score Calculator
Calculate the z-score of a value
Probability Calculator
Calculate the probability of events
Midpoint Calculator
Find the midpoint between two points
Trigonometry Calculator
Calculate sine, cosine, tangent and inverse
kg to Pounds Converter
Convert kilograms to pounds and back
cm to Feet Converter
Convert centimeters to feet and inches
Miles to km Converter
Convert miles to kilometers and back
Celsius to Fahrenheit Converter
Convert temperature between C and F
Feet to Meters Converter
Convert feet to meters and back
Inequality Calculator
Solve and graph linear inequalities
Polynomial Calculator
Add, subtract and multiply polynomials
Linear Equation Calculator
Solve linear equations for x
Statistics Calculator
Mean, median, mode, range, variance and standard deviation
Horsepower Calculator
Calculate horsepower from torque and RPM
Watts to Amps Calculator
Convert watts to amps for DC and AC circuits
Projectile Motion Calculator
Range, max height and flight time of a projectile
Half-Life Calculator
Radioactive decay: remaining amount, time or half-life
Torque Calculator
Calculate torque from force and distance
Fibonacci Calculator
Generate the Fibonacci sequence and the nth term
About math & conversion calculators
Find the right math tool
The Percentage Calculator answers "what is X% of Y" and related questions, while the Percentage Increase and Percentage Change calculators compare two numbers. For homework and stats, the Fraction, Average and Standard Deviation calculators handle the arithmetic, and the Unit Converter switches between metric and U.S. units.
What you need to enter
Most tools just need two or three numbers - a base value and a percentage, two points for a change, or a list of values for an average. Because everything runs in your browser, you can experiment freely and watch the result and formula update instantly.
A worked example
To find 15% of 80, multiply 80 by 0.15 to get 12. To measure growth instead, a value rising from 50 to 65 is a 30% increase: the change of 15 divided by the original 50. The Percentage Change Calculator handles both increases and decreases and shows the same steps.
Frequently asked questions
How do I calculate a percentage of a number?
Convert the percent to a decimal and multiply. For 15% of 80, compute 0.15 ร 80 = 12. The Percentage Calculator does this and shows the working.
What's the difference between percentage change and percentage points?
Percentage change is relative to the starting value (50 to 65 is a 30% increase). Percentage points are the plain difference between two percentages (a rate going from 5% to 7% is a 2-point rise).
Do the calculators show the steps?
Yes. Each math tool displays the formula and the intermediate result, not just the final answer, so you can follow the method or check homework.