Date Calculator
Calculate days between two dates, add or subtract days/weeks/months/years from a date, and count business days excluding weekends. Perfect for project deadlines, event planning, legal notices, vacation planning, and historical calculations. See results in multiple units with detailed conversions.
How It Works
1. Choose Calculation Type
Select what you want to calculate: days between two dates, add/subtract time from a date, or count business days (excluding weekends).
2. Enter Your Dates
Input dates using the calendar picker. For add/subtract mode, choose whether to add or subtract and select the time unit (days, weeks, months, or years).
3. View Results
See the result with breakdown in multiple units: days, weeks, months, and years. Business days mode shows weekdays only (no weekends).
4. Use Conversions
Reference the conversion table to see results in hours, minutes, and seconds. Common use cases help you apply date calculations practically.
Examples
Example 1: Days Until Event
Type: Days Between Dates Start Date: December 11, 2025 End Date: July 4, 2026 Results: Total Days: 205 days Weeks: 29 weeks Months: 6 months (approx) Business Days: 147 weekdays Counting down to Independence Day 2026.
Example 2: Add Time to Date
Type: Add/Subtract Dates Starting Date: January 1, 2025 Operation: Add Value: 90 days Results: Result Date: April 1, 2025 (Tuesday) Total Days: 90 days Weeks: 12 weeks Months: 3 months 90 days notice or project deadline from January 1.
Example 3: Business Days
Type: Business Days Start Date: January 6, 2025 (Monday) End Date: January 17, 2025 (Friday) Results: Total Days: 11 days Business Days: 9 weekdays (Excludes Saturday Jan 11 & Sunday Jan 12) Work days between two dates for project planning.
Example 4: Subtract Months
Type: Add/Subtract Dates Starting Date: December 15, 2025 Operation: Subtract Value: 6 months Results: Result Date: June 15, 2025 Total Days: 183 days Weeks: 26 weeks Months: 6 months Looking back 6 months from a date.
Frequently Asked Questions
How do you calculate days between two dates?
To calculate days between two dates, subtract the earlier date from the later date and convert the difference to days. The calculator accounts for leap years, different month lengths, and calculates the exact number of days. For example, from January 1 to January 31 is 30 days (31 - 1 = 30). The calculation is precise regardless of month or year boundaries.
What are business days and how are they counted?
Business days (also called weekdays or working days) are Monday through Friday, excluding weekends (Saturday and Sunday). To count business days, the calculator goes through each day between the start and end dates and only counts days that are not Saturday or Sunday. Note: This does not exclude holidays, only weekends. 5 business days typically means one work week.
When I add a month to a date, what happens if the day doesn't exist?
When adding months to a date, if the result day doesn't exist in the target month, the date rolls to the last day of that month. For example: January 31 + 1 month = February 28 (or 29 in leap year), since February doesn't have 31 days. May 31 + 1 month = June 30, since June has 30 days. The calculator handles this automatically.
How do leap years affect date calculations?
Leap years have 366 days instead of 365 (extra day: February 29). Leap years occur every 4 years, except century years not divisible by 400. For example: 2024 is a leap year, 2100 is not, but 2000 was. The date calculator automatically accounts for leap years when calculating days between dates or adding/subtracting time. This ensures accuracy across year boundaries.
Can I calculate dates in the past or future?
Yes, the date calculator works for any past or future dates. You can calculate historical dates (e.g., days since a historical event) or future dates (e.g., days until a deadline). There are no restrictions on date range. For add/subtract mode, you can add time to go into the future or subtract time to go into the past from any starting date.