Time Duration Calculator

Work out the duration between two dates and times

This time duration calculator measures the exact elapsed time between a start date and time and an end date and time. It breaks the result into days, hours, and minutes for easy reading, and also provides totals in minutes, hours, and seconds for use in spreadsheets, timesheets, or other tools. It is useful for planning schedules, checking how long an event will take, logging work time, calculating contract durations, and confirming gaps between appointments.

To use it, enter a start date and time and an end date and time using the format YYYY-MM-DD HH:MM (for example, 2026-03-06 09:30), then click Calculate. If the end date and time is before the start, the calculator will return an error — this keeps the output unambiguous and avoids interpreting negative durations that are usually just input mistakes.

The most common use case is straightforward: you have a start time and an end time on the same day or across a few days and you want to know the total duration quickly. For instance, a meeting from 10:15 to 14:45 is 4 hours and 30 minutes. A project that runs from March 1 at 08:00 to March 14 at 17:00 spans 13 days, 9 hours, and 0 minutes. The calculator handles all of these without you needing to count manually or worry about crossing midnight.

Duration calculations can catch people out when they cross daylight saving time boundaries. In many countries, clocks shift forward or backward once or twice per year, which means an interval that appears to span 24 hours by the clock might actually be 23 or 25 hours of real elapsed time. This calculator uses your device’s local time rules, so it will reflect those shifts when your start and end times span a clock change. If you are scheduling something that needs to be precise around a DST change — such as a flight connection or a contract deadline — pay close attention to which side of the change each time falls on.

For situations where you need to calculate only business hours or exclude weekends, this calculator is not the right tool — it measures raw elapsed time with no exclusions. For that kind of calculation you would need a business days calculator that filters the result by working days and hours. This calculator is best suited to simple elapsed time questions where you want the full unfiltered duration.

Assumptions and how to use this calculator

• Enter dates and times in YYYY-MM-DD HH:MM (24-hour) format, e.g. 2026-03-06 09:30. The ISO format YYYY-MM-DDTHH:MM is also accepted.
• Always include leading zeros: 09:05, not 9:5. Months and days also need leading zeros if they are single-digit.
• The calculator uses your device’s local time zone. Results reflect any daylight saving time rules that apply.
• Elapsed time is measured to the minute. Seconds within a minute are not accounted for.
• This calculator measures total elapsed time only. It does not filter out weekends, holidays, or non-working hours.

Common questions

Why does it say my date/time format is invalid?

The expected format is YYYY-MM-DD HH:MM using a 24-hour clock. Common causes of the error are using slashes or dots as date separators instead of hyphens (e.g. 06/03/2026 instead of 2026-03-06), using 12-hour time with AM/PM instead of 24-hour time, or missing leading zeros (e.g. 9:5 instead of 09:05). Check these first if you see a format error.

Does this include daylight saving time changes?

Yes, because the calculation uses your device’s local time rules. If your local time zone observes daylight saving time and the interval crosses a DST boundary — for example, a start time before the clocks change and an end time after — the result will reflect the actual elapsed time, which will be one hour more or less than the calendar difference suggests.

Can I calculate durations spanning multiple weeks or months?

Yes. Enter any start and end date and the calculator will compute the full duration, no matter how large the gap. The output shows days, hours, and minutes as well as total hours and total minutes, which makes it easy to read long durations at a glance.

What is the “total seconds” figure used for?

Total seconds and total minutes are single numbers that represent the full duration without any unit breakdown. They are useful when pasting results into a spreadsheet, a timesheet system, or an API that expects a duration in a single unit. It is easier to sum or compare flat numbers in those contexts than to recalculate from a days-hours-minutes breakdown.

Can I use this for billing or timesheet purposes?

You can use it to calculate the total minutes or hours between two logged times, which is the typical input for a timesheet or invoice. However, this calculator does not apply rounding rules (such as rounding to the nearest 15 minutes) or billing rates. Use the total minutes or hours result as your raw time input, then apply any rounding or rate rules in your billing tool or spreadsheet.