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Date & Time calculators
Explore 8 free date & time calculators. Calculate in your browser with clear inputs, worked examples, and transparent methods.
8 calculators available
- Date Calculator
Add or subtract calendar years, months, weeks, and days from a date with month-end handling.
- Day Counter
Count elapsed and inclusive calendar days, weeks, weekdays, and weekend days between two dates.
- Day of the Week Calculator
Find the weekday, day of year, ISO week, quarter, and distance from today for any Gregorian date.
- Hours Calculator
Calculate elapsed work time between clock times, including overnight shifts and an unpaid break.
- Sleep Calculator
Plan bedtimes or wake times around approximate 90-minute sleep cycles and a settling allowance.
- Time Calculator
Add or subtract two hour-minute-second durations and convert the result to total units.
- Time Duration Calculator
Calculate elapsed time between two clock times, including overnight spans and break deductions.
- Time Zone Calculator
Convert a local date and time between fixed UTC offsets, including dates that cross midnight.