Date Calculator
Three calculators in one: the duration between two dates, adding or subtracting a period, and exact age. With a breakdown in business days and weeks.
Difference between two dates
- Breakdown
- 0 years, 0 months, 30 days
- Weeks
- 4 wk and 2 d
- Business days
- 21
Date calculations without the pitfalls
Counting days by hand tends to go wrong: months of different lengths, leap years, clock changes. This calculator works on calendar dates, which avoids the one-day errors caused by the switch to and from daylight saving time.
The result is given in several forms, because the right answer depends on what you need it for: a total in days for a deadline, a breakdown in years and months for seniority, a number of business days for a project plan or a leave balance.
How to use it
- Pick the tab that matches your calculation: difference, adding or subtracting a period, or age.
- Enter the dates. The result updates immediately, with nothing to submit.
- For a stay or a period of leave, tick "include the end day" so the last day is counted.
Frequently asked questions
The calculation keeps Monday to Friday and excludes Saturdays and Sundays. Public holidays are not deducted, since they vary by country and sometimes by region.
It depends on what you are counting. For a deadline between two dates, leave the box unticked. For a length of stay or a number of leave days, tick it: the last day counts.
No. The calculations work on calendar dates rather than durations in hours, so the switch to and from daylight saving time does not introduce a one-day gap.
Age is broken down into completed years, then whole months, then remaining days, as on official records. The calculator also shows the total number of days lived and the time until the next birthday.
