Free Online Calculators

Convert length measurements between meters, feet, inches, centimeters, kilometers, and miles.

Convert temperatures between Celsius, Fahrenheit, and Kelvin using the standard scale formulas.

Convert weight and mass between kilograms, grams, pounds, ounces, and stone using exact definitions.

Calculate the exact number of days, weeks, and months between any two calendar dates.

Calculate the tip amount, total bill, and per-person share when splitting a restaurant bill evenly.

Calculate how an investment grows over time with compound interest and monthly contributions, with a year-by-year growth chart.

Calculate your fixed monthly loan payment, total amount paid, and total interest from principal, rate, and term.

Calculate the fixed monthly deposit needed to reach a savings goal, given current savings and interest rate.

Calculate simple interest (I = P·r·t) and the final balance on a principal, where interest accrues only on the original amount.

Estimate how many years it takes to double an investment using the Rule of 72, compared against the exact compounding formula.

Calculate return on investment as a percentage, plus the net gain or loss, from the amount invested and the final value.

Calculate the compound annual growth rate that takes a starting value to an ending value over a number of years.

Find out how long it takes to pay off a credit card balance with a fixed monthly payment, and how much interest you'll pay along the way.

Calculate Body Mass Index from height and weight, in metric (cm/kg) or imperial (in/lbs) units.

Estimate body fat percentage from neck, waist (and hip) circumference using the U.S. Navy circumference method, in metric (cm) or imperial (in) units.

Find X% of Y, work out what percent one number is of another, or calculate percent change between two values.

Solve ax² + bx + c = 0 with the quadratic formula, reporting the discriminant and both roots, including complex roots.

Find the greatest common divisor and least common multiple of two integers using the Euclidean algorithm.

Calculate a circle's radius, diameter, area, and circumference from either the radius or diameter.

Solve a right triangle's missing side, area, perimeter, and angles from either its two legs or its hypotenuse and one leg.