Date Calculator
Date difference, add/subtract days, business days, and days until/since a date.
A date calculator finds the number of days between two dates, adds or subtracts days from a date, and counts business days excluding weekends.
Examples
Days Between Dates
Add Days to a Date
Frequently Asked Questions
What counts as a business day?
Does this handle leap years?
Quick Tips
- •Remember that months have different lengths — calculations account for 28-31 day months automatically.
- •Use business day mode for project planning to exclude weekends from your timeline.
- •The days-until mode is handy for countdown timers to upcoming events or deadlines.
A date calculator finds the number of days between two dates, adds or subtracts days from a date, and counts business days excluding weekends.
How to Use This Calculator
Choose a mode: days between two dates, add a number of days to a date, add business days (excluding weekends), or days until/since a specific date. Enter the dates in the fields. Click Calculate. Useful for deadlines and project planning.
Understanding the Formula
Difference in days; business days exclude weekends.
Examples
Days Between Dates
From January 1, 2025 to March 15, 2025 is 73 calendar days, or approximately 52 business days (excluding weekends).
Add Days to a Date
Adding 90 days to June 1, 2025 gives August 29, 2025. Adding 90 business days gives October 1, 2025.
Frequently Asked Questions
What counts as a business day?
A business day is any weekday (Monday through Friday). This calculator excludes Saturdays and Sundays but does not account for public holidays.
Does this handle leap years?
Yes. The calculator correctly accounts for leap years, so February 29 is included in leap year calculations.
Assumptions & Limitations
- Based on the Gregorian calendar; does not handle historical calendar systems.
- Leap years are accounted for in all date calculations.
- Business day calculations exclude Saturdays and Sundays but do not account for public holidays.