Free online calculators

Tells you which weekday a given date falls on.

Converts a number of days into hours.

Converts a number of hours into days.

Checks whether years are leap years.

Turns a number of seconds into hours, minutes and seconds.

Adds up a pasted list of numbers.

Calculates the span between two dates in days, hours and other units.

Converts a clock time into decimal hours, useful for timesheets.

Converts hours, minutes and seconds into total seconds.

Truncates a clock time to a coarser unit.

Shows voltage drop, power loss and maximum run length for a wire gauge in AWG or mm2, copper or aluminium.