Days Between Dates Calculator
Pick two dates and get the exact number of days between them, along with the same span expressed in weeks, months, and years. You can choose whether to include the end date in the count. That is the difference between "days between" and "days from start to end inclusive", and it matters for deadlines, billing periods, and medication schedules.
This is the tool for questions like: how many days until my vacation, how long ago was an event, how many days are in a project timeline, or how many days late is a payment. The count uses real calendar dates, so leap years and month lengths are always correct.
How it's calculated
Days = end date − start date (in calendar days)
Adding one to the result includes the end date itself. Weeks are the day count divided by 7; the months and years breakdown counts full calendar months first, then leftover days.
Worked example
From 1 January 2026 to 30 August 2026 there are 241 days, which is 34 weeks and 3 days, or 7 months and 29 days. Including the end date makes it 242 days.
Frequently asked questions
›Should I include the end date?
It depends on the question. "How many days until the deadline" usually excludes today but includes the deadline. Rental or medication periods usually count both the first and last day. The toggle lets you match either convention.
›How do leap years affect the count?
A leap year adds 29 February to the calendar, so spans that cross it contain one extra day. The calculator works with real dates, so this is automatic.
›How many days are in each month?
January 31, February 28 (29 in leap years), March 31, April 30, May 31, June 30, July 31, August 31, September 30, October 31, November 30, December 31.
›Can this count business days?
The main result counts all calendar days. As a rule of thumb, business days are roughly 5/7 of the total, minus any public holidays in the span.
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