How this date duration calculator works
The duration between two dates is simply how much time separates them. The most common way to express it is in whole days — the number of midnights you cross going from the start date to the end date. This calculator gives you that total and then breaks it down into weeks, a calendar-accurate years/months/days figure, total months, total hours, and the number of business days.
By default the end date is not counted, so the gap from Jan 1 to Jan 31 is 30 days. If you tick Include end date, both endpoints are counted and the same range becomes 31 days. If the end date falls before the start date, the tool simply swaps them so the result is never negative.
| Range (start → end) | Days (default) | Days (inclusive) | Business days |
|---|---|---|---|
| Jan 1 → Jan 8 | 7 | 8 | 5 |
| Jan 1 → Jan 31 | 30 | 31 | 21 |
| Jan 1 → Feb 1 | 31 | 32 | 22 |
| Jan 1 → Dec 31 | 364 | 365 | 260 |
Reference note: calculations use the Gregorian calendar and your device's local date. Leap years are handled automatically, and business days count Monday through Friday only — public holidays are not deducted.
Frequently asked questions
- How many days between two dates?
- Count the whole days from the start date to the end date. By default that is the gap between the two days; tick "Include end date" to count the final day too, adding one. The calculator shows the total automatically.
- How do I count business days only?
- Business days are weekdays — Monday to Friday — so you count every day in the range and exclude every Saturday and Sunday. The calculator shows the business-day total next to the calendar-day total.
- Does it include the end date?
- By default the end date is not counted, so Jan 1 to Jan 31 is 30 days. Tick "Include end date" to count both endpoints, which makes the same range 31 days.
- How many weeks is that?
- Divide the total number of days by 7. The whole number is the count of full weeks and the remainder is the leftover days — for example 30 days is 4 weeks and 2 days.
- How do I calculate months between dates?
- Count complete calendar months from the start date, then the remaining whole days, borrowing days from the previous month when the end day is earlier than the start day. The tool shows that calendar-accurate years, months and days breakdown.
- How many days until a future date?
- Set the start date to today and the end date to the future date — the total days is the countdown. The calculator defaults the end date to today, so just change the dates to count forward.