Percentage Calculator
Result = percentage ÷ 100 × number.
Calculators15 free tools
Calculators
Everyday numbers, with the working shown.
All processing happens on your device.
Percentage Change
Change = (new − original) ÷ |original| × 100.
CalculatorsPercentage Difference
Difference = |a − b| ÷ ((a + b) / 2) × 100.
CalculatorsRatio Calculator
Divides both integer terms by their greatest common divisor.
CalculatorsFraction Calculator
Uses common denominators for addition/subtraction and cross products for multiplication/division, then reduces by GCD.
CalculatorsAverage Calculator
Arithmetic mean = sum of values ÷ count.
CalculatorsMedian Calculator
Sorts values; returns the middle value or mean of the two middle values.
CalculatorsStandard Deviation Calculator
Welford’s algorithm accumulates squared deviations.
CalculatorsGCD Calculator
Euclid’s remainder algorithm finds the greatest common divisor.
CalculatorsLCM Calculator
LCM(a,b) = |a ÷ GCD(a,b) × b|, folded across the list.
CalculatorsPrime Number Checker
Tests divisibility by 2 and odd integers through the square root.
CalculatorsScientific Calculator
A bounded recursive-descent parser supports + − * / % ^, parentheses, pi, e, sin/cos/tan, inverse trig, sqrt, abs, ln, log, exp, floor and ceil.
CalculatorsRandom Number Generator
Web Crypto rejection sampling gives each integer in the inclusive range equal probability.
CalculatorsDecimal ↔ Fraction
Finite decimals become an integer over a power of ten, then reduce by GCD.
CalculatorsRoman Numeral Converter
Uses standard subtractive Roman notation: IV, IX, XL, XC, CD and CM.
Calculators