Duration Calculator
Calculate the precise time between two dates. Get results in years, months, days, hours, minutes, and seconds. Perfect for age calculations, project planning, and business day counting.
How to Use the Duration Calculator
- Select your timezone - The calculator will detect your browser timezone automatically
- Set start date and time - Choose when your duration begins
- Set end date and time - Choose when your duration ends
- Optional: Enable business days - Check the box to exclude weekends from the calculation
- View results - See the duration broken down in multiple formats
Understanding the Results
Human Readable Duration
The most natural way to express duration. For example: "2 years, 3 months, 15 days" gives you an intuitive understanding of the time span.
Total Units
See the complete duration expressed as a single unit. This is useful for calculations and comparisons:
- Total Days: The entire duration in days (including fractional days)
- Total Hours: Convert the whole duration to hours
- Total Minutes: Express as minutes for precise tracking
- Total Seconds: The most granular measurement
Business Days
When you enable "Exclude weekends," the calculator counts only Monday through Friday. This is essential for project planning, SLA calculations, and workplace scheduling. Weekends (Saturday and Sunday) are automatically excluded from the count.
Breakdown by Unit
See how the duration splits into individual components: years, months, days, hours, minutes, and seconds. This hierarchical view helps you understand the magnitude of time in familiar units.
Common Use Cases
Age Calculator
Calculate someone's exact age by setting their birthdate as the start date and today as the end date. Get precise results in years, months, and days—perfect for legal documents, medical records, or birthday planning.
Project Duration
Track how long a project has been running or will run. Use business days mode to calculate actual working days, excluding weekends. Essential for sprint planning and deadline management.
Event Countdown
Calculate how much time remains until an important event. Whether it's a product launch, wedding, or deadline, see exactly how many days, hours, and minutes are left.
Service Level Agreements (SLAs)
Monitor response times and resolution periods. Use business days to match your support hours and accurately track whether you're meeting SLA commitments.
Historical Analysis
Calculate time spans between historical events. Useful for research, documentation, and understanding how long processes or projects actually took to complete.
Tips for Accurate Calculations
- Timezone matters: Make sure both dates use the same timezone for consistent results. The calculator handles timezone conversions automatically.
- Business days exclude weekends only: Holidays are not automatically excluded. For holiday-aware calculations, manually adjust your dates.
- End before start: If your end date is before the start date, the calculator will still work and show you the duration with a note.
- Precision: All calculations are precise down to the second, using the industry-standard Luxon datetime library.
Related Tools
- Date Math Calculator - Add or subtract time from dates
- Timestamp Converter - Convert between Unix timestamps and human-readable dates
Learn More
Want to understand how duration calculations work? Check out these resources: