Date Calculator – Days Between Dates

This date calculator does two jobs. Days between dates counts the exact number of days from one date to another – also in weeks, months and years, with the number of weekdays and weekend days. Add or subtract finds the date a number of days, weeks, months or years before or after any date, with an option to count only business days.

How to Count the Days Between Two Dates

1. Choose Days between dates and pick a start and end date. The start date is today by default.
2. Tick Include the end date if both the first and last day should count – for example, a hotel stay counted in days rather than nights, or an event that runs from Monday through Friday.
3. Read the total in days, the breakdown in years, months and days, and the number of weekdays.

Example: from January 1, 2026 to December 31, 2026 is 364 days. Including the end date it is 365 days – the whole year. From July 4, 2026 to December 25, 2026 is 174 days, or 24 weeks and 6 days.

Why "Including the End Date" Changes the Answer

By default, a date difference counts the days you move forward: from Monday to Tuesday is 1 day. That is how ages, deadlines and loan interest are usually counted. But if you are counting days of an event – a conference from the 10th to the 12th – you probably mean 3 days, so include the end date. When a contract or form says "within 30 days," check which way it counts.

How to Add or Subtract Days From a Date

Choose Add or subtract, pick a start date and enter years, months, weeks and days. The calculator adds years and months first, then weeks and days:

• 90 days from today – common for return windows, probation periods and visa stays.
• 6 months from a date – months have different lengths, so the result keeps the same day of the month. Adding one month to January 31 gives February 28 (or 29 in a leap year), because February has no 31st.
• Business days – tick the option to skip Saturdays and Sundays, for shipping estimates and deadlines measured in working days. Federal holidays such as Thanksgiving and Christmas are not skipped, so add them yourself if they fall in the period.

Useful Date Facts

• A normal year has 365 days (52 weeks and 1 day); a leap year has 366.
• Leap years are divisible by 4, except century years not divisible by 400. 2028 is a leap year; 2100 will not be.
• A year has 260 or 261 weekdays, depending on which day it starts.
• Months have 28 to 31 days, so "one month" is not a fixed number of days – the average month is 30.44 days.

Common Uses

To find someone's exact age, use the age calculator. To total hours rather than days, use the hours calculator.

Age Calculator Hours Calculator Time Card Calculator Percentage Calculator