Date Difference Calculator
Need to know how many days there are between two dates? This calculator gives the difference in years, months and days, the total number of days and weeks, and how many of those days fall on weekdays and weekends.
Last reviewed:
- Difference
- 0 years, 11 months, 30 days
- Total days
- 364
- In weeks
- 52 weeks and 0 days
- Weekdays (Mon–Fri, both dates counted)
- 261
- Weekend days (Sat–Sun)
- 104
- Weekday counts do not exclude public holidays.
It is useful for notice periods, project timelines, loan or deposit durations, pregnancy and travel planning, and any deadline where you need an exact count.
How to use this calculator
- Pick the start date and the end date.
- Choose whether to count the end date as well. Counting both the first and last day adds one day.
- Read the difference in years, months and days, plus the totals.
- Check the weekday count if you are planning working days.
Formula and variables
Total days = End date − Start date (+ 1 if both dates are counted)
- Years, months, days - whole months are counted first, then the days left over.
- Weekdays - Monday to Friday days between the dates, with both dates included.
Leap years are handled automatically. Public holidays are not excluded from the weekday count.
Worked example
How long is it from 1 January 2026 to 31 December 2026?
| Start date | 1 January 2026 |
|---|---|
| End date | 31 December 2026 |
| Difference | 11 months, 30 days |
| Total days | 364 (365 if both dates are counted) |
| Weeks | 52 weeks |
- From 1 January to 1 December is 11 whole months, and from 1 December to 31 December is 30 days.
- 2026 has 365 days. The gap between the first and last day is 364 days.
- 364 ÷ 7 = 52 weeks exactly.
What changes the result
- Including the end date. Some purposes (like a stay at a hotel) count nights; others (like days of leave) count both the first and last day.
- Leap years. A span that includes 29 February has one extra day.
- Month lengths. Months have 28 to 31 days, so '1 month' is not a fixed number of days.
- Holidays. Weekday counts do not remove public or local holidays.
Benefits and practical uses
- Count days exactly for notice periods and deadlines.
- Plan working days between two dates.
- Work out durations for deposits, loans and leave.
- Avoid manual calendar counting mistakes.
Assumptions and limitations
- The Gregorian calendar and whole dates only. Times of day are ignored.
- If the end date is earlier than the start date, the dates are swapped.
- Weekends are Saturday and Sunday.
Frequently asked questions
How do I calculate the number of days between two dates?
Subtract the earlier date from the later one. The calculator does this exactly and accounts for leap years.
Should I include the last day?
It depends on your purpose. Leave it unticked to get the gap between the dates, or include it if both the first and last day count, such as days of leave.
Does it count business days?
It counts Monday to Friday days. Public holidays are not removed.
How are months counted?
Whole calendar months are counted first, then the remaining days, which is why the result may differ from days ÷ 30.
Can the end date be earlier than the start date?
Yes. The calculator swaps them and tells you.
References
Page last reviewed on . This calculator gives estimates for planning only; it is not financial advice and not an offer from any lender.