When to use a time duration calculator

From shift scheduling to cross-timezone meeting planning, knowing the exact gap between two times is a daily need for remote workers, operations teams, and travellers.

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Shift scheduling

Calculate the exact length of a work shift — from clock-in at 06:45 to clock-out at 15:15 — without mental arithmetic or calendar apps.

✈️

Flight durations

Find how long a flight actually takes by entering the departure and arrival local times, then switching to timezone mode for cross-zone routes.

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Cross-timezone calls

Enable timezone mode to check how much time separates two scheduled events in different cities — useful for global team coordination.

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Workout tracking

Log the duration of a training run, cycling session, or workout block between any start and end time down to the minute.

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Billable hours

Convert project start and end times into precise decimal hours for invoicing — the decimal hours field does that conversion automatically.

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Event timing

Plan video recordings, live streams, or conference sessions by calculating the precise gap between segments.

FAQ

Time Duration Calculator — FAQ

How do I calculate hours between two times?

Enter the start time and end time in the fields above. The calculator instantly shows the gap in hours and minutes, along with the total in minutes, seconds, and decimal hours.

What does 'timezone-aware' mode do?

When enabled, each time is converted to UTC before the difference is calculated. This means 9:00 AM New York (UTC-4) and 5:00 PM London (UTC+1) correctly produce a 4-hour gap rather than an 8-hour one.

What happens if the end time is before the start time?

The calculator assumes the end time is on the next day and adds '+1 day' to the result. This covers overnight shifts (e.g. 22:00 to 06:00 = 8 hours).

How are decimal hours calculated?

Decimal hours = total minutes ÷ 60. A duration of 7 hours and 30 minutes equals 7.50 decimal hours, which is the standard format for payroll and billing.

Can I use this for payroll or invoicing?

Yes. Enter your shift start and end times to get the exact decimal-hours figure. For billing across timezones, enable timezone-aware mode so the duration reflects the true elapsed time.