Free Date Calculator - Date Difference & Interval Tool
Calculate the exact difference between any two dates in years, months, days, weeks, and hours. Perfect for counting down to events, calculating age, measuring project timelines, or determining deadlines and durations for personal and professional planning.
How to Use
Select a start date and end date using the date pickers, or click the "From Today" button to use today as your starting point. The calculator instantly shows the difference broken down into years, months, days, total weeks, and total hours. You can also add or subtract days from a specific date.
Common Use Cases
- Event Planning: Count days until a wedding, vacation, or deadline
- Age Calculation: Determine exact age in years, months, and days
- Project Management: Measure the duration between project milestones
- Billing & Invoicing: Calculate the number of days between service dates
- Legal Deadlines: Determine exact intervals for contracts and agreements
- Fitness Tracking: Track the time elapsed since starting a fitness program or habit
Features
- Years, months, and days breakdown for precise interval measurement
- Total days and total weeks displayed for quick reference
- Hours calculation for short-duration intervals
- "From Today" quick button for immediate date math starting from today
Privacy
All calculations happen locally in your browser. No dates or data are transmitted.
Date Math Limitations
Date intervals can be interpreted differently depending on time zone, daylight saving time, inclusive versus exclusive counting, and legal or business rules. For contracts, payroll, court deadlines, immigration dates, or compliance timelines, verify with the relevant official rule.
Quick Answer
Use the calculator to find elapsed time between two dates or to add/subtract days from a date. For deadline-sensitive work, confirm whether the start and end dates should be counted inclusively.
Last reviewed: July 2026.