Calculator Tools

Convert length, weight, volume, temperature, data and more between any units.

Work out percentages, discounts, tax and tips — with the working shown.

Calculate the time between dates, someone's age, or a date in the future.

Loan repayments, compound interest, profit margin, break-even and ROI.

Roots, exponents, factorials, GCD, LCM, primes and factorisation.

Mean, median, mode, standard deviation, quartiles and outliers from any data set.

Read a resistor's colour bands, or find the bands for a target value.

Enter any two of voltage, current, resistance and power to find the other two.

Find Vout from two resistors, or solve for the resistor a target Vout needs.

Find the series resistor an LED needs, from supply voltage, forward voltage and target current.

AWG wire diameter, cross-section and resistance, plus voltage drop over a run.

Type a chemical formula and get its molar mass, broken down element by element.

Solve for moles, volume or molarity — enter any two, get the third.

C1V1 = C2V2 — enter any three values to find the fourth, for diluting a stock solution.

Convert between pH, pOH, [H⁺] and [OH⁻] — with an acidic/neutral/basic read.

PV = nRT — solve for pressure, volume, amount or temperature, given the other three.

The Moon's phase, illumination percentage and age for any date.

Sunrise, sunset, solar noon and day length for any place and date.

Convert between a calendar date and the continuous day count astronomy uses.

The dates and UTC times of all four equinoxes and solstices for any year.

What you'd weigh on the Moon, Mars, Jupiter and every other body in the solar system.