Date Duration Calculator
Result
Duration11 months, 30 days
Total days364
Total weeks52 weeks, 0 days
Total hours8736
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Date Duration Calculator — free online calculator.
Formula
Duration = end date − start date (in days), with a calendar breakdown into years, months and days
- Date Duration Calculator calculates its result from End Date, Start Date In Days. It uses the formula Duration = end date − start date (in days), with a calendar breakdown into years, months and days. Change any input to recalculate the result instantly.
- The main inputs are Start date, End date, Include end day. Enter them in the units and format shown in the calculator.
- Use the units, labels and assumptions shown beside each input so the formula is applied consistently.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Date Duration
Inputs
- Start date: 2026-01-01
- End date: 2026-12-31
- Include end day: no
Using End Date = 2, Start Date In Days = 11, the calculated result is -9.
Sample result: Calculating…
Frequently asked questions
What does the Date Duration calculate?
Date Duration Calculator — free online calculator.
Which values should I enter?
Enter Start date, End date, Include end day using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Duration = end date − start date (in days), with a calendar breakdown into years, months and days.
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.