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Use the fields in the tool above and keep units and formats consistent.
Count the days between any two dates, inclusive or exclusive, or add and subtract days, weeks and months to find deadlines, notice periods and due dates.
Result date
2026-01-11
Date results are estimates for planning and should be checked against current official rules or professional advice where applicable.
Counting days on a wall calendar is slow, and it goes wrong easily across months. This date calculator handles it two ways. It finds the gap between two dates. It can also add or subtract days, weeks, months or years from any date.
From 15 January 2026 to 26 October 2026 is 284 days. Count both the start and end dates and it becomes 285. The same gap is 9 months and 11 days, or 40 weeks and 4 days.
Adding 90 days to 1 March 2026 lands on 30 May 2026. That is useful for notice periods, payment terms and visa validity. Subtracting works the same way, for example to find when a 45-day window began.
The one-day difference trips people up more than anything else. An exclusive count measures the gap, like nights in a hotel. An inclusive count includes both ends, like days on a leave application.
| Situation | Usual count | Example |
|---|---|---|
| Hotel stay | Exclusive | 10 to 12 June is 2 nights |
| Leave application | Inclusive | Monday to Friday is 5 days |
| Event or festival | Inclusive | 10 to 12 June is 3 days |
| Age or tenure | Exclusive | Counted from the start date onward |
When a contract says "within 30 days", check whether day one is the notice date or the day after. Legal and government deadlines often follow their own counting rules.
Months have 28, 29, 30 or 31 days, so "one month later" is not a fixed number of days. Adding a month to 31 January has no matching date in February. Most date tools move to the last valid day instead, which is 28 February in 2026.
Leap years add another wrinkle. A year is a leap year if it divides by 4, except century years not divisible by 400. So 2000 was a leap year but 1900 was not. The next leap day falls on 29 February 2028.
Age works the same way as any date gap. Someone born on 14 August 1990 is 36 years, 2 months and 12 days old on 26 October 2026. That is 13,222 days in total. Forms for exams and government jobs often ask for age on a specific cut-off date.
For anything legal or medical, confirm the final date with the authority or doctor involved. The calendar arithmetic is exact, but weekend and holiday rules vary.
Use the fields in the tool above and keep units and formats consistent.
Review the result shown in the output area.
Confirm that the result matches your situation before using it for a decision.
Calendar-day arithmetic is applied to the selected start date.This describes the core logic used by the tool. Check any assumptions that may affect your result.
Use accurate inputs and keep units consistent.
Review the assumptions before using the result for a decision.
Compare important results with an independent or official source.
Find the normal difference between the dates, then add one. From 1 June to 30 June is 29 days apart, but 30 days when both dates count. Leave applications and event bookings usually rely on the inclusive figure.
Ninety days after 26 October 2026 is 24 January 2027. Months differ in length, so the answer always depends on the start date. Enter any start date and number of days to get the exact result for your situation.
Yes, leap years are built into the calculation, so a range that includes 29 February counts it as a day. The next leap day falls in 2028. This matters for long spans like loan tenures, service periods and age.
Divide the total number of days by seven. From 15 January to 26 October 2026 is 284 days, which is 40 weeks and 4 days. Pregnancy timelines and project schedules are often tracked in weeks this way.
Count the total days, then remove weekends and public holidays. November 2026 has 30 days, of which 21 fall on Monday to Friday. Holidays differ by state and employer in India, so subtract those separately.
Calendar days include every day, weekends and holidays too. Working days count only the days a business normally operates, usually Monday to Friday. A 30-day notice period typically means calendar days unless your contract says otherwise.
Enter the date and the calculator shows the weekday alongside the result. For example, 15 August 2027 falls on a Sunday. This helps you check whether a deadline lands on a weekend or public holiday before you commit.
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