Date Difference Calculator

From 1 October to 6 October 2026, there are 5 elapsed days. But if you count the 1st and the 6th as well as every date in between, you get 6 dates. Both answers can be useful. The right one depends on what you are counting.

You can also express the gap in weeks or in years, months and days. Before using the result, decide which units you need and whether the start and end dates should be included.

Elapsed days tell you how far apart two dates are. An inclusive count tells you how many calendar dates the range covers. When the dates are in order, counting both ends adds one to the elapsed difference.

For example, a stay from 1 October to 6 October lasts five nights. Leave covering every date from 1 to 6 October covers six calendar dates, before any workplace rules are applied.

If the start and end dates are the same, the elapsed difference is zero days. An inclusive count gives one date. This is a useful way to check what a form means when it asks for the “number of days.”

For a calendar breakdown, count full years, then full months, then the days left over. From 15 June 2024 to 6 October 2026, the result is 2 years, 3 months and 21 days, or 843 elapsed days.

You can follow the calculation in steps: from 15 June 2024 to 15 June 2026, then to 15 September 2026, and finally to 6 October. Each step uses the actual calendar.

Dividing 843 by 365 or 30 will not give that same breakdown. A year can have 365 or 366 days, and a month can have 28 to 31 days. Calendar months and years are not fixed blocks of days.

Divide the number of days by seven. The whole number gives the complete weeks, and the remainder gives the extra days.

So 100 days is 14 weeks and 2 days. The 843-day interval above is 120 weeks and 3 days. Month lengths do not affect this conversion because a week is always seven days.

For a deadline exactly 100 days after a date, add 100 calendar days. If the instruction says “within 100 days” or tells you to exclude the starting date, follow that wording when deciding how to count.

To count working days, you need to know which days the organization works and which holidays it observes. A Monday-to-Friday office and a Monday-to-Saturday office will have different totals for the same period.

For Monday 1 June through Sunday 7 June 2026, including both dates:

A holiday reduces the total only if it falls on a day that would otherwise be counted. A holiday on an already excluded Sunday does not remove another day. If the same holiday date appears twice in a list, count it only once.

Indian offices, schools and banks do not all follow one working calendar. Use the weekend pattern and holiday list that apply to your organization. The calculator can count those dates, but your employer's rules decide how they apply to attendance or leave.

One calendar month after 15 January is 15 February, a gap of 31 days. One month after 15 February 2025 is 15 March, a gap of 28 days.

Month endings need extra care. This calculator uses the last available day when the target month does not contain the starting day. Adding one month to 31 January 2025 gives 28 February. Subtracting one month from 28 February then gives 28 January, rather than taking you back to the 31st. The move to February has lost the original day information.

For a contract or schedule written in months, calculate in months. If it specifies a fixed number of days, count that number of days instead.