Date Calculator
Add or subtract time from dates, find specific dates like "the 3rd Friday of next month", and calculate business days excluding weekends and holidays.
Date Calculator
Add or subtract time from dates, find specific dates, and calculate business days
Date Calculation
How to Use the Date Calculator
Add/Subtract Time
Start with any date and add or subtract days, weeks, months, or years. Perfect for planning events, calculating deadlines, or determining ages.
- • Add or subtract any amount of time
- • Handles leap years automatically
- • Multiple output formats available
- • Shows relative descriptions
Find Specific Dates
Find dates like "the 2nd Tuesday of March" or "next Friday". Useful for scheduling recurring events or finding holidays.
- • Find next occurrence of any weekday
- • Locate specific occurrences in months
- • Handles edge cases automatically
- • Detailed date information provided
Business Days
Calculate dates excluding weekends and optionally holidays. Essential for business planning, shipping estimates, and project timelines.
- • Excludes weekends automatically
- • Custom holiday exclusion support
- • Shows calendar vs business day spans
- • Multiple date format outputs
Common Date Calculations
Project Planning
- • Add 30 days for project deadline
- • Subtract 2 weeks for review period
- • Calculate business days for delivery
- • Find milestone dates
Personal Events
- • Calculate exact age in days
- • Find anniversary dates
- • Plan vacation schedules
- • Determine retirement dates
Business Operations
- • Invoice due dates
- • Contract expiration dates
- • Shipping and delivery estimates
- • Payroll processing dates
Legal & Compliance
- • Statute of limitations deadlines
- • Filing deadlines
- • Notice periods
- • Compliance dates
Financial Planning
- • Investment maturity dates
- • Loan payment schedules
- • Tax deadlines
- • Budget planning periods
Event Planning
- • Find third Thursday of month
- • Schedule recurring meetings
- • Plan holiday schedules
- • Coordinate availability
Understanding Date Formats
| Format | Example | Use Case | Notes |
|---|---|---|---|
| Short | 1/15/2024 | Quick reference, space-constrained displays | US format (MM/DD/YYYY) |
| Medium | Jan 15, 2024 | General use, readable format | Common in documents and reports |
| Long | Monday, January 15, 2024 | Formal documents, invitations | Includes day of week |
| ISO | 2024-01-15 | Programming, databases, international use | Universal standard format |
Business Days vs Calendar Days
Business Days Include
- ✅ Monday through Friday
- ✅ Regular working days
- ✅ Days when businesses typically operate
- ✅ Non-holiday weekdays
Used for shipping estimates, payment processing, and official deadlines.
Business Days Exclude
- ❌ Saturdays and Sundays
- ❌ Federal and bank holidays
- ❌ Company-specific holidays
- ❌ Regional holidays (optional)
Exclusions can vary by industry, country, and specific business practices.
Common US Federal Holidays
Fixed Date Holidays
- • New Year's Day (Jan 1)
- • Independence Day (Jul 4)
- • Veterans Day (Nov 11)
- • Christmas Day (Dec 25)
Monday Holidays
- • Martin Luther King Jr. Day (3rd Mon in Jan)
- • Presidents Day (3rd Mon in Feb)
- • Memorial Day (Last Mon in May)
- • Labor Day (1st Mon in Sep)
- • Columbus Day (2nd Mon in Oct)
Variable Date Holidays
- • Thanksgiving (4th Thu in Nov)
- • Juneteenth (Jun 19)
- • Good Friday (varies)
- • Easter (varies)
Date Calculation Tips
Best Practices
- • Always specify time zones for important deadlines
- • Consider regional holidays for international business
- • Use ISO format (YYYY-MM-DD) for data storage
- • Account for leap years in long-term calculations
- • Document date format assumptions clearly
- • Test edge cases like month-end dates
Common Pitfalls
- • Confusing MM/DD/YYYY vs DD/MM/YYYY formats
- • Forgetting leap years in February calculations
- • Not accounting for different month lengths
- • Ignoring daylight saving time changes
- • Assuming all years have exactly 365 days
- • Forgetting to exclude weekends from business days
Frequently Asked Questions
How does the calculator handle leap years?
The calculator automatically accounts for leap years when adding or subtracting months and years. Leap years occur every 4 years, except for years divisible by 100 (unless also divisible by 400).
What happens when adding months to month-end dates?
When adding months to dates like January 31st, the calculator uses JavaScript's built-in date handling. Adding 1 month to Jan 31 results in Feb 28 (or 29 in leap years) because February doesn't have 31 days.
Can I exclude custom holidays from business day calculations?
Yes! Enable the "Exclude holidays" option and enter your custom holiday dates in YYYY-MM-DD format, separated by commas. The calculator will skip these dates when counting business days.
How accurate are the "find date" calculations?
The find date feature is very accurate and handles edge cases like months with fewer than 5 occurrences of a weekday. If you ask for the "5th Friday" and the month only has 4 Fridays, it returns the 4th (last) Friday.
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