Date Calculator
Add or subtract time from a date, or count the days between two.
Every date you enter stays in the page and is never uploaded.
Counting forward ninety days from a contract date, or working out how many working days are left before a deadline, is the sort of thing a wall calendar makes tedious and a spreadsheet makes error-prone.
More about Date Calculator
This does three jobs. It adds or subtracts days, weeks, months and years from a date. It reports the gap between two dates several ways at once, because "days between" genuinely means different things to different people. And it counts working days, excluding weekends and any holidays you supply.
The inclusive and exclusive counts are both shown rather than one being chosen for you. Between 1 January and 2 January there is one day if you are counting nights, and two if you are counting days you are away. Picking one silently leaves half the readers with an off-by-one they will not notice until it matters, so both appear side by side and are labelled.
For adding months, the convention is clamping: 31 January plus one month is the end of February, not the 1st or 3rd of March. That is stated on the page as well as in this paragraph, because two calculators using different conventions can differ by days and neither will tell you which one it picked.
There is deliberately no built-in holiday calendar. Public holidays differ by country, by region within a country, and by year, and a wrong built-in list is worse than none because nobody thinks to check it. Paste your own dates instead.
- Add or subtract days, weeks, months and years from any date
- Days between two dates, counted inclusively and exclusively, both labelled
- Weekday and weekend split for any range
- Working days with your own holiday list, one date per line
- Month arithmetic clamped to the end of the month, and it says so
- A holiday that falls on a weekend is not subtracted twice
How to use it
- 1Choose whether you are adding, measuring a gap, or counting working days.
- 2Set the start date, and the end date if the mode needs one.
- 3For adding, pick the amount, the unit and the direction.
- 4For working days, paste your holidays one per line as YYYY-MM-DD.
- 5Read the result, and copy it if you need it elsewhere.
Questions
Is the count inclusive or exclusive?
Both are shown and labelled. Between 1 and 2 January there is one day exclusive, two inclusive, and which you want depends on what you are counting.
What does adding one month to 31 January give?
The last day of February, so 28 or 29 depending on the year. The result is clamped into the target month rather than rolling forward into March.
Why are there no public holidays built in?
Because they differ by country, region and year, and a wrong built-in calendar is worse than none since nobody checks it. Paste the dates that apply to you.
What counts as a working day?
Monday to Friday, minus any dates you list as holidays. A holiday that already falls on a weekend is not subtracted a second time.
Does daylight saving affect the day count?
No. Days are counted on the calendar, so a 23 or 25 hour day still counts as exactly one day.