Date Duration Calculator
Calculate the duration between two dates in years, months, weeks, and days. Choose whether to include the start and end dates in the count.
Enter a start date and end date.
How it works
Enter a start date and an end date. The calculator uses UTC calendar dates only (time of day is ignored).
Years, months, and days use the same calendar-age breakdown as the Age Calculator—whole years, then months, then days between the adjusted boundaries.
Total days follow the same inclusive/exclusive boundary rules as the Date Range Calculator. Turn start or end inclusion on or off to match your counting policy.
Total weeks are whole weeks (total days ÷ 7, rounded down). They are a simple day-count conversion, not a separate month-based estimate.
Common uses
Age-adjacent spans, project durations, contract terms, reporting periods, and planning timelines when you need both a calendar breakdown and total days.
Age-adjacent calculations
Measure elapsed time in years, months, and days between two life or milestone dates.
Project durations
See how long a phase or deliverable window lasts in calendar terms.
Contract terms
Express agreement length as years, months, days, and total calendar days.
Reporting periods
Define fiscal or operational windows with explicit boundary inclusion.
Planning timelines
Compare total days and approximate months for schedule communication.
FAQ
- How do I calculate duration between two dates?
- Enter the start and end dates, then review years, months, days, total days, and total weeks. Adjust include start/end if your policy counts boundary dates differently.
- What is the difference between date duration and total days?
- Date duration is the calendar breakdown (years, months, days). Total days is a single day count for the selected inclusive or exclusive range method.
- Can I include the start date?
- Yes. Enable Include start date when day one should count. You can also include or exclude the end date independently.
- What happens if the end date is before the start date?
- The calculator shows a validation message. End date must be on or after the start date.
Similar Tools
- Date Difference CalculatorFind the exact difference between two dates in days, hours, minutes, and seconds.
- Days Between DatesCalculate the number of days between two calendar dates.
- Date Range CalculatorCalculate date ranges with inclusive or exclusive boundaries, plus optional business-day totals.
- Age CalculatorFind your exact age in years, months, and days.
- Hours Between Dates CalculatorCalculate total hours, days, and minutes between two date-times (UTC).
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