Time Duration Calculator

Calculate Hours Between Two Times

The Time only mode is designed for a start time and end time when the calendar date is not important. It is useful for meetings, travel segments, study periods, machine runtime, events and other elapsed-time checks. If the ending time is earlier than the starting time, the calculator can automatically interpret the end as occurring on the next day.

Calculate Duration Between Dates and Times

Use Date & time mode when an interval spans multiple calendar dates. The browser converts each local date-time into a timestamp and subtracts the start from the end. The result is then broken into whole days, hours, minutes and seconds while also showing the same interval as decimal hours, total minutes and total seconds.

This is useful for project elapsed time, event duration, turnaround checks, travel planning, logs and any situation where a duration can exceed 24 hours. The calculation uses the time zone rules of the device running the browser. If you need to compare two different world time zones, use the dedicated Time Zone Converter instead.

Duration Formula and Totals

For complete date-times, the underlying method is duration = end timestamp − start timestamp. For a time-only interval that crosses midnight, one 24-hour day is added to the ending clock time before the subtraction.

A duration of 1 day, 5 hours and 30 minutes is therefore 29.5 total hours, 1,770 total minutes, 106,200 total seconds, or 1.2292 decimal days. Showing several equivalent totals makes the result easier to reuse in spreadsheets, reports, scheduling and other calculations.

Useful Time-Difference Features

• Swap: exchange start and end values without retyping them.
• Use now: insert the current local time or date-time into either side of the calculation.
• Quick examples: load common daytime, overnight and multi-day intervals to understand the behavior immediately.
• Recent calculations: keep a small local history for quick reference; it is stored only in your browser and can be cleared at any time.
• Copy, save and share: keep the main duration together with the total hours, minutes, seconds and calculation method.

Time Duration vs Work Hours

This page measures elapsed clock time. It does not automatically remove lunch breaks, weekends, holidays or non-working hours. For employee shifts and time sheets, use the Time Card Calculator or Hours Calculator. For business-hour deadlines across working schedules, use the SLA Deadline or Working Hours Between Dates calculators.

Keeping these concepts separate is important: an elapsed duration of 10 hours does not necessarily mean 10 billable or payable working hours.

Frequently Asked Questions

How do I calculate the time between two times?

Select Time only, enter the start and end times, and press Calculate Duration. The result includes the readable duration plus total hours, minutes and seconds.

Can it calculate across midnight?

Yes. Keep the next-day option enabled. For example, an end time of 2:00 AM can be interpreted as occurring after a start time of 10:00 PM.

Can I calculate more than 24 hours?

Yes. Switch to Date & time mode and enter the full start and end date-times.

Why might daylight-saving changes affect the answer?

Date-time mode uses your browser's local time-zone rules. In regions that change clocks for daylight saving time, the actual elapsed duration across a transition can differ from a simple wall-clock comparison.