Time Duration Calculator
This calculator finds the elapsed time between two clock times — useful for a workday, a shift, or any gap measured in hours and minutes rather than calendar dates. It handles both ordinary daytime spans and overnight shifts that run past midnight.
How to use the time duration calculator
- Enter the start time and the end time using the time picker (12-hour or 24-hour, depending on your device).
- If the end time is on the following day — an overnight shift, for example — switch “Does the end time fall on the next day?” to Yes.
- Read the elapsed time in hours and minutes, and in decimal hours for payroll-style calculations.
Formula
Elapsed time = end time − start time, adding 24 hours if the shift is marked as crossing midnight. Decimal hours divide the minutes by 60 (so 15 minutes is 0.25 hours), which is the form most timesheets expect.
Worked examples
A working day
9:15 AM to 5:30 PM is 8 hours 15 minutes — 8.25 hours in decimal.
An overnight shift
10:00 PM to 6:30 AM the next day, marked as crossing midnight, is 8 hours 30 minutes — 8.5 hours in decimal.
Clock time versus calendar time
Why this is not the same as the date calculators
The other tools on this page work with calendar dates and can span any number of days. This one works purely with a time of day — a clock position between 12:00 AM and 11:59 PM — and measures the gap between two such positions, optionally allowing exactly one midnight crossing. It does not know about specific calendar dates at all, which is exactly right for questions like “how long is my shift” that do not care which date it happened to be.
Decimal hours, for payroll and billing
| Minutes | Decimal hours |
|---|---|
| 15 | 0.25 |
| 30 | 0.5 |
| 45 | 0.75 |
| 10 | 0.1667 (rounds to 0.17) |
Timesheets and invoices very often want decimal hours rather than “hours and minutes”, since decimal hours can be summed and multiplied by an hourly rate directly.
Common uses
- Working out the length of a work shift, including overnight shifts.
- Converting a clocked-in/clocked-out pair of times into billable hours.
- Checking how long a scheduled event or meeting block runs.
For a gap measured in days rather than hours, use the days between dates calculator instead.
Practice problems
Try these yourself first, then check your answer. The answers come from the calculator above.
- How many hours and minutes are there between 8:00 AM and 4:30 PM?
Show answer
Elapsed time: 8h 30m
Common mistakes to avoid
- Leaving “crosses midnight” set to No for an overnight shift — the tool will flag the end time as earlier than the start time and ask you to switch it, rather than silently giving a wrong (negative) answer.
- Mixing 12-hour and 24-hour entry without the AM/PM marker — the time picker supplied by your browser handles this automatically, so typing directly is rarely necessary.
- Forgetting that decimal hours are not the same as minutes: 8.25 hours is 8 hours 15 minutes, not 8 hours 25 minutes.
Frequently asked questions
How do I calculate hours between two times?
Enter the start and end time and read the “Elapsed time” row. For an overnight span, switch the next-day option to Yes.
How do I convert the result to decimal hours for payroll?
Use the “In decimal hours” row — it is already divided out, for example 8 hours 15 minutes shown as 8.25.
What if the end time is earlier than the start time?
That is only valid for an overnight span. Switch “Does the end time fall on the next day?” to Yes; otherwise the tool will ask you to check the times.
Does this handle different time zones?
No — both times are assumed to be on the same clock. For times in different time zones, convert them to the same zone first.
Reviewed September 26, 2026 by the SolveCalcPro editorial team. Found a mistake? Tell us; see our editorial policy.