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Date Calculator
Add or subtract days from a date, or count the days between two.
Date Calculator tool
Add or subtract from a date
Days between two dates
0
Total days
0
Days inclusive
0
Weeks
0
Working days
About the Date Calculator
Date Calculator answers the two questions that come up whenever a deadline is involved. The first panel adds or subtracts a period from a date: thirty days from today, six weeks before a launch, three months after a contract starts. The second counts the gap between two dates, in total days and in working days.
Working days matter more than total days for most planning, because a thirty-day window containing eight weekend days is not thirty days of work. The calculator counts Monday to Friday by default and lets you choose which days count as the weekend, since that varies between countries.
All the awkward parts of the calendar are handled properly: month lengths differ, leap years exist, and adding one month to 31 January has to land somewhere sensible. Here it lands on the last day of February rather than overflowing into March, which is the convention most scheduling systems use.
How to use the Date Calculator
- Pick a starting dateToday is filled in for you, and can be changed.
- Add or subtract a periodEnter days, weeks, months or years, and choose which direction.
- Read the resulting dateIt appears with its weekday and how far away it is.
- Or use the second panelEnter two dates to count the total days, weeks and working days between them.
Features
- Add or subtract days, weeks, months and years
- Counts total days, weeks and working days between two dates
- Configurable weekend, since it differs by country
- Shows the weekday of every result
- Correct handling of month lengths and leap years
- Month arithmetic clamps to the last valid day rather than overflowing
- Copy any result
Who uses this tool
The date calculator is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:
- Working out a deadline a set number of days ahead
- Counting working days available before a delivery date
- Finding the date a notice period or trial ends
- Planning a schedule backwards from a fixed launch date
- Checking how many days are left until an event
Frequently asked questions
What happens when I add a month to the 31st?
The result clamps to the last day of the target month, so one month after 31 January is 28 or 29 February rather than spilling into March. This is the convention most calendars and scheduling systems follow.
Which days count as working days?
Monday to Friday by default, with the weekend configurable because it is not Saturday and Sunday everywhere. Public holidays are not included, since they differ by country and region, so subtract them yourself for an exact figure.
Is the end date included when counting between two dates?
The total is the gap between them, so counting from the 1st to the 8th gives seven days. An inclusive count, which would give eight, is shown alongside for when you need the number of calendar days a period covers.
Does it handle dates before 1970 or far in the future?
Yes. Calculations use real calendar dates across a very wide range, so historical dates and distant deadlines both work.
Are leap years accounted for?
Yes, including the rule that a century year is only a leap year when divisible by 400, which is why 2000 was one and 1900 was not.
Is my data stored?
No. Dates are handled in your browser and nothing is saved or transmitted.
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