About Date Difference Calculator
This date difference calculator tells you how much time lies between two dates. Pick a start and an end date, and it shows the gap in years, months and days, plus the total number of days and the same total as weeks and days. If you enter the dates in reverse order, the tool swaps them so you still get a positive result.
A second card adds or subtracts a number of days from a start date and shows the resulting date with its weekday; use a negative number to go back in time. The count measures the days between the dates and does not include the start day, so add one if you need an inclusive count. Calculation happens in your browser.
How to use Date Difference Calculator
- 01
Pick a start and an end date.
- 02
See years, months, days and total days.
- 03
Or add/subtract days from a date.
When to use it
- Count the days left until a deadline, wedding, exam or holiday.
- Measure how long a project, contract or employment period lasted.
- Find the date that is 30, 60 or 90 days after an invoice date.
- Work out a due date or return date by adding days to a start date.
- Find which weekday a date falls on after adding or subtracting days.
Frequently asked questions
How do I calculate the number of days between two dates?
Pick the From date and the To date. The tool shows the total days between them, and also the same gap in years, months and days, and in weeks and days.
Is the start date or end date included in the count?
The result counts the days between the two dates, not including the start day. If you need both days counted, such as for a booking that includes the first and last day, add one day to the total.
How do I add days to a date?
Use the Add or subtract days card. Choose a start date and enter the number of days, for example 30. The tool shows the new date including the weekday and full date in your browser language.
Can I subtract days from a date?
Yes. Enter a negative number in the days field, such as -14, and the tool returns the date that many days before the start date. This is handy for finding a notice or deadline date.
What happens if the end date is before the start date?
In the Days between two dates card, the tool swaps the two dates and returns the same gap as a positive number, so the order of the dates does not change the result.
Are leap years and month lengths handled?
Yes. Dates are counted using the real calendar, including different month lengths and 29 February in leap years. Nothing is uploaded; everything runs in your browser.