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.
Duration
Example1 year, 5 months, and 14 days
Based on
- Start date
- January 1, 2024
- End date
- June 15, 2025
- Counting
- Inclusive (start and end included)
From January 1, 2024 to June 15, 2025, the duration is 1 year, 5 months, and 14 days.
More detail
- Total days
- 532 days
- Total weeks
- 76 weeks
Next step: Employment Duration Calculator
When to use this calculator
Use this calculator whenever you need a calendar-style breakdown (years, months, days) between two dates rather than a single day count—project durations, contract terms, or any span best expressed the way people naturally describe elapsed time.
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.
Inputs
Start date and end date
The two dates bounding the span.
Include start date / Include end date
Whether each boundary date counts toward the total, matching the Date Range Calculator's options.
How the calculation 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.
Worked example
Start date: 15 January 2023. End date: 20 June 2025.
Duration: 2 years, 5 months, 5 days.
Total days: 887. Total weeks: 126 complete weeks.
The years/months/days breakdown and the total-days figure describe the same span two different ways—use whichever format matches how your contract or policy states duration.
Edge cases
Include vs exclude boundary dates
Including both the start and end dates adds two extra days to the total-days figure relative to excluding both.
Leap year spans
A span that crosses 29 February gains one extra day compared to an equivalent span in years without a leap day, visible in the total-days figure even when the years/months/days breakdown looks similar.
End date before start date
The calculator shows a validation message. End date must be on or after the start date.
Same-day range
A start and end date on the same day produces a duration of 0 years, 0 months, and 0 or 1 days depending on the include-boundary settings.
Related Date & Business Days Calculators
The Business Days vs Calendar Days Guide explains when weekends and holidays count and which day type applies to deadlines, invoices, and contracts.
The How Business Days Are Calculated Guide and Business Days Between Dates Guide cover the counting rules behind every business-day tool on this site.
The Business Days Calculator and Working Days Calculator count weekdays between two known dates, excluding weekends and optional US federal holidays.
The Add Business Days To Date, Subtract Business Days From Date, and Business Day Offset calculators move a single date forward or backward by a business-day count.
The Business Days Until Date Calculator counts business days remaining from today or a custom date to a target deadline.
The Days Between Dates Calculator counts every calendar day between two dates, including weekends—use it instead of the business-day tools when weekends should count.
The Date Range Calculator and Date Duration Calculator break a range into calendar-day totals or a years/months/days breakdown, with inclusive or exclusive boundary options.
The Add or Subtract Days Calculator shifts a single date forward or backward by days, weeks, or months.
The Age Calculator applies the same calendar breakdown used by Date Duration to a birth date, expressed as years, months, and days.
The Hours Between Dates and Date Difference calculators measure elapsed time between two date-times down to hours, minutes, and seconds.
The Date Format Converter, Unix Timestamp Converter, and Timezone Converter handle format and zone conversion for a single instant rather than a span between two dates.
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.
- How is this different from the Age Calculator?
- Same underlying calendar-breakdown engine—the Age Calculator is framed specifically for a date of birth and an as-of date, always ending at today by default. This calculator works with any two dates.
Related Guides
Browse all Date & Business Days
Similar Tools
- Employment Duration CalculatorFind exact length of service in years, months, and days from a joining date to today or a last day of employment.
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- 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.
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