Date and time calculators

22 calculators

Date and time calculators convert clock formats, compute age, tick a live age from a date of birth, and find spans between calendar dates using the rules described on each page.

Calendar math follows the tool’s stated convention (for example 24-hour mapping of AM/PM). Time-zone and leap-second edge cases are called out only where the How it works text mentions them. Date tools are free — no account to get started.

Printable Date Time formula sheet →

Clocks calculators

12/24-hour time and timezone offset.

Calendar spans calculators

Days, weeks, months, and hours from a reference date.

Age and duration calculators

Age, live ticking age, work hours, and how-long-until helpers.