Math calculators
Percentages, fractions, and everyday math made quick.
Percentages and everyday numbers
Percentage calculator
Find a percentage of a number, work out what percent one value is of another, or measure the change between two numbers.
Percent change calculator
Measure the percentage increase or decrease between an original value and a new value.
Fraction calculator
Add, subtract, multiply, or divide two fractions and get the simplified result, its decimal, and the mixed-number form.
Rounding calculator
Round any number to a set number of decimal places or to the nearest 1, 10, 100 or 1000.
Statistics calculator
Paste a list of numbers and get the count, sum, mean, median, mode, range, variance, and standard deviation instantly.
School and grades
Geometry, units, and number systems
Geometry calculator
Calculate area, perimeter, circumference, and diagonals for common shapes using standard formulas.
Square footage calculator
Work out the area of a rectangular space from its length and width, in square meters, feet or yards.
Unit converter
Convert between length, mass, and temperature units with exact factors and live results.
Roman numerals converter
Convert numbers to Roman numerals and Roman numerals back to numbers, both ways, instantly.
Prime number calculator
Check whether a number is prime, factorize it into primes, or list every prime up to a limit.