Date & Time

Time Duration Calculator

Free instant time duration calculator with formula. Calculate hours and minutes between two times, including overnight shifts.

By Calculator Suite Pro Editorial Team | Last updated March 18, 2026

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Start timeEnd time

Shift crosses midnight

Total Duration

8h 0m

Total Minutes

480

Decimal Hours

8.00

Direct answer

Time Duration Calculator gives an instant result from your inputs. A time duration calculator finds the difference between two clock times. It is commonly used for work shifts, study sessions, workout routines, and any scenario where you track hours and minutes. Formula snapshot: Decimal hours are computed as totalMinutes / 60, useful for timesheets. Example: Start: 09:00, End: 17:00 -> 8h 0m (480 minutes, 8.00 hours).

About this calculator

A time duration calculator finds the difference between two clock times. It is commonly used for work shifts, study sessions, workout routines, and any scenario where you track hours and minutes.

This calculator supports the common overnight case (crossing midnight). If your end time is earlier than your start time, enable 'Shift crosses midnight' to treat the end time as the next day.

If you need timezone conversion (for example, '9am New York time in Los Angeles'), use the Timezone Difference Converter first.

How it works

A quick explanation of the logic behind the results, so you can trust what you see.

Times are converted into total minutes from midnight.
If the shift crosses midnight, we add 24 hours (1440 minutes) to the end time so the interval stays positive.
Total minutes are converted into hours + remaining minutes for a readable duration.
Decimal hours are computed as totalMinutes / 60, useful for timesheets.

Formula used

These are the core formulas and logic rules used by this calculator.

Decimal hours are computed as totalMinutes / 60, useful for timesheets.

Common use cases

Below are common real-world scenarios where this calculator is useful.

Work shift tracking (hours worked)
Overnight shifts (support, healthcare)
Gym sessions and workout duration
Study session tracking
Break and lunch duration checks
Travel planning (departure/arrival times)
Call center or freelance time logs
School class duration planning

How to use

Enter a start time.
Enter an end time.
Enable 'Shift crosses midnight' if the end time is on the next day.
Review total duration (hours/minutes), total minutes, and decimal hours.
Adjust times to compare multiple shifts or sessions quickly.

Common mistakes to avoid

These are the issues that most often cause confusing results.

Forgetting to enable 'crosses midnight' for overnight shifts.
Entering the wrong time format when switching between 12-hour and 24-hour clocks elsewhere.
Assuming a negative duration is valid (it usually indicates the next-day case).
Using this tool for different timezones without converting first.
Relying on decimal hours when you need hours and minutes for reporting.

Tips and notes

Use total minutes for strict time calculations (for example, payroll rules).
Use decimal hours if your timesheet requires fractional hours.
If your end time is earlier than start time, it usually means the shift is overnight.
For multi-day durations, use Date Difference instead of time-only duration.
Combine this with the Timezone Converter to schedule across regions, then measure a local duration if needed.
If you are tracking multiple breaks, calculate each break separately and add totals.

Glossary

Quick definitions for common terms used in this calculator.

Crosses midnight

A shift that starts late in the day and ends after midnight on the next day.

Decimal hours

Hours expressed as a decimal (totalMinutes / 60), used by some payroll systems.

Examples

Standard workday

Input: Start: 09:00, End: 17:00

Output: 8h 0m (480 minutes, 8.00 hours)

Short session

Input: Start: 14:20, End: 15:05

Output: 0h 45m (45 minutes, 0.75 hours)

Overnight shift

Input: Start: 22:30, End: 06:15 (crosses midnight)

Output: 7h 45m (465 minutes, 7.75 hours)

FAQ

How do I calculate overnight shifts?

Enable 'Shift crosses midnight'. If end time is earlier than start time, it indicates an overnight interval.

Does it include seconds?

No. This calculator focuses on hours and minutes, which covers most scheduling and timesheet needs.

What is decimal hours used for?

Decimal hours are helpful for timesheets (for example, 7.75 hours) while hours/minutes are better for readability.

Can I calculate multi-day time spans?

For multi-day spans, use Date Difference (dates) and only use this tool for daily clock-time intervals.

Why do I get a weird result when end time is earlier?

That typically means the shift ends on the next day. Enable the crosses-midnight option.

Can I use this for timezones?

Convert timezones first using the Timezone Converter, then measure local duration if needed.

Is this calculator free to use?

Yes. This calculator is free to use without signup.

Can I use this calculator on mobile?

Yes. The calculator is mobile-friendly and works on desktop as well.

Last updated and references

Last updated: March 18, 2026

Reviewed by Calculator Suite Pro Editorial Team.

For sensitive health and finance topics, review official sources in addition to calculator outputs.

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