Time Duration Calculator
Calculate the duration between two times or two date-times in hours, minutes and seconds — including overnight shifts. Free and instant.
24-hour format, e.g. 09:00 or 17:30:45.
Duration
8h 30m
In hours
8.50 h
In minutes
510 min
In workdays
1.1
8-hour working day
How it works
Duration = end − start, plus 24 hours if the end time is on the next day.
Example: 09:00 → 17:30 = 8h 30m.
Last updated: June 2026
How this calculator is verified
Checked by Rahim Virani on
- Overnight spans add 24 hours rather than returning a negative duration
- 09:00 to 17:30 verified as 8h 30m
- Business-hour mode subtracts a weekend or lunch break correctly
The full verification method is on our how we verify page. Found an error? Tell us and we will re-check it.
When to Use This Calculator
Duration questions appear constantly in work and study life: how long is 5 pm to 10 pm, how many hours between 9 AM and 5:30 PM, or how much time a 9-to-6 shift really covers. This calculator gives the exact hours, minutes and seconds between two times, handles overnight shifts that cross midnight, and reports the result in both clock-time and decimal-hour form for timesheets and billing. The date & time mode extends the same math across days for travel, project windows and event planning. Students use it to plan study blocks, freelancers use it to log billable hours, and night-shift workers use it to track shifts that end after midnight. The workdays figure — total hours divided by eight — makes it easy to see how many full working days a stretch covers.
How to Use This Calculator
- Step 1: Choose the mode — clock times for two times of day, or date & time for two full dates and times.
- Step 2: In clock mode, enter the start and end times in 24-hour format (seconds optional); tick the next-day option for overnight spans.
- Step 3: In date & time mode, pick the start and end date-time values — either order works.
- Step 4: Read the duration in hours, minutes and seconds, plus decimal hours, total minutes and workdays.
Worked Example
A shift from 08:13 to 16:55 lasts 8 hours and 42 minutes — no manual borrowing needed. From 08:13 to 16:07 the answer is 7 hours 54 minutes, because subtracting the minutes requires a carry across the hour boundary. An overnight span from 16:07 to 08:13 the next day runs 16 hours and 6 minutes; tick the next-day option so the result stays positive. Date & time mode extends the same math across days: 09:00 on 10 August to 17:30 on 11 August is 1 day, 8 hours and 30 minutes. Results also come as decimal hours for timesheets and billing.
Tips and Common Mistakes
- •Tip 1: Use 24-hour format everywhere — 5:30 means 05:30 in the morning, not 17:30.
- •Tip 2: For overnight shifts, always tick the next-day option; forgetting it is the most common source of wrong results.
- •Tip 3: The decimal-hours figure is what payroll systems and spreadsheets expect, so use it when filling timesheets.
- ✗Mistake 1: Typing AM or PM into a field that expects 24-hour input, which makes the entry unreadable or misparsed.
- ✗Mistake 2: Adding a break amount in the work-hours tool but not here — this tool measures elapsed time only, so lunch breaks must be subtracted by you.
Expert Note
The decimal-hours output is what payroll systems and Tally/Excel timesheets expect. For overnight shifts, always enable the next-day option — without it, the end time appears earlier than the start time and the result goes negative. Workdays exclude weekends only; Indian public holidays must be subtracted manually.
Sources and References
- •ISO 8601:2019 — Duration format (PnYnMnDTnHnMnS)
- •24-hour clock convention — National Institute of Standards and Technology
Official sources are linked so you can confirm the current rate yourself. Check the linked page for the latest notification before relying on these figures.
Frequently Asked Questions
How do you handle times that cross midnight?
If your end time is earlier than your start time, the calculator assumes it is the next day and adds 24 hours. For overnight shifts, tick 'End time is on the next day' to be sure.
How many hours are between 9 AM and 5:30 PM?
8 hours and 30 minutes. The calculator subtracts the start time from the end time, so 5:30 PM (17:30) minus 9:00 AM (09:00) is 8.5 hours.
Does the result include a lunch break?
No. The tool measures the total clock time between the two times. If you need actual working hours, subtract unpaid breaks yourself.
What is the workdays figure?
It divides the total duration by 8 hours, the standard full-time working day, so you can quickly see how many days a timesheet covers.
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- Date Difference Calculator — Count the exact days, weeks, months, years and business days between two dates, with hours and minutes too
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