Free Calculators & Converters

Pure math formulas. No external data. No tracking. Instant results.

Financial Calculators

Compound Interest

Calculate how investments grow over time with A = P(1 + r/n)^nt

Mortgage Calculator

Monthly payment, total interest, amortization schedule

Hourly to Salary

Convert hourly wage to annual salary (x 2,080 hours)

Tip Calculator

Calculate tip and split between people

Unit Conversions

CM to Feet

Convert centimeters to feet and inches

KG to Pounds

Convert kilograms to pounds

Celsius to Fahrenheit

Temperature conversion with formula

KM to Miles

Convert kilometers to miles

Math Calculators

Percentage Calculator

What is X% of Y? Percent increase/decrease.

BMI Calculator

Body Mass Index — weight(kg) / height(m)²

Decimal to Binary

Number base conversions

Roman Numerals

Convert numbers to and from Roman numerals