Date Calculator
Calculate the difference between two dates, add or subtract time periods, find future or past dates, and count working days. Perfect for planning events, calculating age, and project management.
Calculate Difference Between Dates
Quick Calculations
How to Use the Date Calculator
📅 Date Difference Mode
Select two dates to calculate the exact difference between them. The calculator shows years, months, weeks, days, hours, minutes, and seconds. Enable "Exclude weekends" to count only working days (Monday-Friday).
➕ Add to Date Mode
Choose a starting date and add any combination of years, months, weeks, or days to find a future date. Perfect for calculating due dates, expiration dates, or planning events.
➖ Subtract from Date Mode
Select a date and subtract time to find a past date. Useful for backdating calculations, finding historical dates, or calculating start dates from known end dates.
Common Use Cases
🎂 Age Calculation
Calculate exact age in years, months, and days from birth date to today. Find out how many days you've been alive or calculate someone's age on a specific date.
📊 Project Management
Calculate project duration, find deadline dates, count working days, and plan sprint schedules. Essential for project managers and team leads.
💼 Business Planning
Calculate invoice due dates (Net 30, Net 60), plan campaigns, schedule deliveries, and track contract periods. Count business days for accurate financial calculations.
🎉 Event Planning
Find out how many days until your wedding, vacation, birthday, or anniversary. Plan event schedules and create countdown timers.
📚 Academic Scheduling
Calculate semester lengths, count study days, plan assignment deadlines, and find exact dates for academic calendars.
⚖️ Legal & Financial
Calculate statute of limitations, loan periods, contract durations, and compliance deadlines. Count exact days for legal documentation.
Date Calculation Tips & Tricks
Understanding Date Differences
- The calculator includes both start and end dates in the count
- Working days exclude Saturdays and Sundays but include holidays
- Month calculations account for varying month lengths (28-31 days)
- Leap years are automatically handled in all calculations
Business Days vs Calendar Days
Business days (working days) typically exclude weekends. For accurate business day calculations including holidays, consult your region's holiday calendar. Our calculator excludes weekends when the option is enabled.
Adding Mixed Time Periods
You can combine years, months, weeks, and days in a single calculation. For example, add "1 year, 3 months, 2 weeks, and 5 days" all at once. The calculator handles month-end edge cases automatically.
Frequently Asked Questions
How do I calculate my exact age?
Use Date Difference mode. Enter your birth date as "From Date" and today's date as "To Date". The result will show your exact age in years, months, and days.
What does "working days" mean?
Working days (or business days) are weekdays from Monday to Friday, excluding weekends. When you enable "Exclude weekends", the calculator only counts Monday through Friday.
How do I calculate 90 days from today?
Use Add to Date mode or click the "90 Days from Now" quick button. This is commonly used for invoice payment terms, project deadlines, and trial periods.
Does the calculator account for leap years?
Yes! The date calculator automatically handles leap years. February 29th is correctly recognized, and all calculations spanning leap years are accurate.
Can I calculate past dates?
Yes. Use Subtract from Date mode to go backwards in time, or use Date Difference mode with the earlier date as "To Date" to see how long ago something was.
How are months calculated?
Months are calculated calendar-wise. For example, adding 1 month to January 31st gives February 28th (or 29th in leap years). The calculator intelligently handles month-end dates.
Is the date calculator accurate for historical dates?
The calculator is accurate for dates from year 1 AD to far future dates. It follows the Gregorian calendar used in most of the world today.