Date and time calculators
Date arithmetic is deceptively hard by hand — months vary between 28 and 31 days, leap years add a day every four years, and 'ten days from Monday' means different things depending on whether the count is inclusive. These calculators use real calendar arithmetic rather than a fixed 365-day year, so long spans do not drift.
Both calendar days and working days are reported where relevant, since contracts, notice periods, and project plans usually mean the latter even when they say the former.
Date & Time tools
Age Calculator & Birthday Countdown
Calculate your exact age in years, months, weeks, days, hours, and minutes, plus next birthday countdown.
- Exact age in Years, Months, Days
- Total days, hours, minutes lived
Date Difference & Duration Calculator
Calculate exact days, business days, weeks, months, and years between two dates or add/subtract time from a date.
- Total calendar days
- Business days (excluding weekends)
Frequently Asked Questions
Do these calculators handle leap years?
Yes. They use real calendar arithmetic rather than a fixed 365-day year, so every 29 February in the range is counted. Estimating with 365 days per year drifts by roughly one day every four years.
Does the day count include both the start and end date?
The difference is exclusive by default — 1 March to 8 March is 7 days. Many contracts count both endpoints, in which case add one. Which convention applies depends on your document, not on the arithmetic.
Are public holidays excluded from business-day counts?
No, only weekends. Public holidays vary by country, state, and sometimes industry, so subtract those separately using your own calendar.