Days Between Dates Calculator
This calculator works out how many days there are between two dates — for example between today and a deadline, a contract start and end, or two historical events. Besides the total number of days, it shows the same span expressed in weeks, approximate months and years, and the number of business days (Monday to Friday). You can choose whether the final day is counted or not, which matters for things like rental periods or notice periods.
Days between the dates
days
In weeks
Business days
In months (approx.)
In years (approx.)
Business days exclude Saturdays and Sundays, but not local public holidays. Months and years are approximate (30.44 days and 365.25 days respectively).
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How it works
The calculator converts both dates to their position on the calendar and subtracts them to get the exact number of whole days between them. If you tick "include the end day", one extra day is added, which is the convention used when both the first and the last day count (for example, a hotel stay counted in nights versus days). Weeks are the total days divided by seven. Months and years are approximations based on the average lengths of 30.44 and 365.25 days, so they will not always match a calendar month-by-month count exactly. Business days are counted by stepping through the range and skipping every Saturday and Sunday; public holidays are not removed because they vary by country and region.
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Preguntas frecuentes
- Does the calculator count the start and end day?
- By default it counts the number of full days between the two dates, which means the start day is the reference point and the end day is included as the final boundary — the difference between 1 January and 2 January is 1 day. If you tick "include the end day", both endpoints are counted, so the same pair returns 2 days. Choose the option that matches how you are counting.
- What are business days and how are they counted?
- Business days (also called working days) are Mondays through Fridays. The calculator steps through every day in the range and counts only those that are not a Saturday or Sunday. It does not subtract public holidays, because holidays differ from one country, state, or company to another.
- Why are the months and years marked as approximate?
- Because calendar months have different lengths (28 to 31 days) and years can have 365 or 366 days, there is no single exact conversion from a number of days to months. The calculator uses the astronomical averages of 30.44 days per month and 365.25 days per year, which gives a close estimate but may differ by a day or two from a strict calendar count.
- Can I calculate the number of days until a future date?
- Yes. Set the start date to today and the end date to your target — a birthday, a holiday, an exam, or a deadline — and the total days field is your countdown. You can also work backwards by setting a past date as the start to see how many days have elapsed since an event.
- Does it handle dates in different years or across leap years?
- Yes. The calculation is based on real calendar dates, so ranges that span several years, cross a leap day, or move between centuries are all handled correctly. February 29 is included only in the years where it actually exists.