Days Between Dates Calculator

How to Calculate Days Between Two Dates

Calculating the exact number of days between two dates requires accounting for different month lengths (28, 29, 30, or 31 days) and leap years (February 29 every 4 years, with exceptions). Our calculator handles all of this automatically using the Gregorian calendar. Simply pick a start and end date — the order doesn't matter, the tool always shows the absolute difference.

Business Days Calculator — Count Weekdays Only

Business days are weekdays (Monday through Friday), excluding Saturday and Sunday. This is essential for:

Project deadlines: "The project is due in 30 business days" means 30 weekdays, not 30 calendar days (which would be about 6 weeks).

Legal timelines: Many legal deadlines (court filings, response periods, notice requirements) are counted in business days.

Shipping estimates: Delivery times like "5-7 business days" exclude weekends.

Payroll: Calculating working days in a pay period, vacation days used, or PTO balances.

Add or Subtract Days from a Date

Need to know "What date is 90 days from today?" or "What was the date 60 days ago?" Our Add/Subtract mode calculates this instantly. Enter a start date, choose add or subtract, enter the number of days, and get the result. Toggle business days mode to add only working days — perfect for calculating "The contract expires 45 business days from signing."

Common Date Calculations

90 days from today: Commonly used for probation periods, trial expirations, and quarterly planning. Use the Add mode with 90 days.

30 days from today: Monthly billing cycles, subscription renewals, 30-day notice periods.

180 days from today: Semi-annual reviews, 6-month visa durations, insurance policy periods.

365 days from today: Annual renewals, one-year anniversaries, lease term calculations.

Days in Each Month — Quick Reference

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. A leap year occurs every 4 years (divisible by 4), except for years divisible by 100 (not a leap year), unless also divisible by 400 (leap year again). Example: 2024 was a leap year, 2100 will not be.

Include vs Exclude End Date

The difference between "days between" and "days including" can be confusing. By default, counting from January 1 to January 3 gives 2 days (Jan 2 and Jan 3). If you toggle "Include end date," it gives 3 days (Jan 1, Jan 2, and Jan 3). Use "include" when both the first and last day should count — for example, hotel stays (check-in day and check-out day both count) or event durations.