Duration Calculator
Break time between two date-times into years, months, days, hours, and minutes. Full duration calculator for contracts, projects, and long spans.
How to Use
- Enter the start date and time with as much precision as needed.
- Enter the end date and time.
- Click Calculate breakdown for the full multi-unit span.
- Read years, months, days, hours, and minutes in the result.
- Copy the structured breakdown into reports or emails.
Input Field Guide
- Start
- Beginning date-time of the span. Seconds supported via the datetime control.
- End
- Ending date-time. Must follow start chronologically.
Understanding Your Results
The result stacks calendar years, months, and days, then hours and minutes within the final partial day-similar to describing how long something lasted in speech. Supplemental totals may show absolute days or hours for spreadsheet cross-checks.
Features
- Years through minutes decomposition
- Date-time precision including overnight spans
- Leap-year aware month stepping
- Detail totals for audit
- Copy and share support
- Local-only processing
Formula & Calculation Logic
Subtract calendar components iteratively from start toward end: years, months, days, then convert remaining milliseconds to hours and minutes.
Real-World Use Cases
- Project phase length in mixed units
- Rental and equipment hire with hour precision
- SLA reporting with day and hour components
- Long service or membership spans
- Post-mortem timelines with granular breakdown
Practical Examples
Start 1 Jan 2024 09:00, end 15 Apr 2026 17:00 -> 2 years, 3 months, 14 days, 8 hours.
Start 10 Mar 2026 23:30, end 11 Mar 2026 01:15 -> 0 years, 0 months, 0 days, 1 hour, 45 minutes.
Benefits
- Readable mixed-unit output for stakeholders
- Avoids manual calendar walking
- Private for contractual timestamps
- Pairs with simpler tools for quick checks
Tips & Best Practices
- Use time-duration-calculator when you only need total hours.
- Include minutes when partial-hour SLAs apply.
- Verify timezone context separately for global teams.
Common Mistakes to Avoid
- Omitting time-of-day when hours should count.
- Expecting business-day duration-weekends count in calendar mode.
- Confusing with adding duration to a date-use date calculator instead.
Frequently Asked Questions
What units does the duration calculator return?
Years, months, days, hours, and minutes between the two date-times.
When should I use duration vs time-duration?
Use duration for full breakdowns; use time-duration for compact hours-minutes-seconds elapsed totals.
Does it include seconds in the headline?
Headline focuses on minutes; sub-minute precision may appear in detail chips.
Can spans cross years and leap days?
Yes. Calendar rules handle February 29 and varying month lengths.
Is timezone applied automatically?
It uses the values you enter locally. Convert zones first with the timezone calculator if needed.
What if start and end are identical?
All units read zero.
Can I measure only calendar days without time?
Set times to midnight on both ends or use day counter for date-only spans.
Is duration data uploaded?
No. Breakdown runs in your browser.