How do I calculate the time duration between two times?

Enter a start time and end time using 24-hour or 12-hour format. The calculator shows the exact duration in hours, minutes, and seconds, plus the total in decimal hours.

Can I calculate duration across midnight (overnight)?

Yes. If the end time is earlier than the start time, the calculator assumes the end time is the following day and correctly calculates the overnight duration.

How do I calculate total hours worked in a day?

Enter your clock-in time as the start time and clock-out time as the end time. The result shows total hours worked in both HH:MM:SS and decimal format for timesheet use.

What is the difference between decimal hours and hours/minutes?

Decimal hours express time as a single number — 1 hour 30 minutes = 1.5 hours. This format is used in invoicing, payroll, and project management. Hours:minutes format (1:30) is used for clocks and schedules.

Can I use the time duration calculator for multiple days?

The time duration calculator measures intervals within a 24-hour period. For multi-day durations, use the Date Difference Calculator, which supports full days, hours, and minutes across any date range.

How do I convert minutes to decimal hours?

Divide the minutes by 60. For example: 45 minutes ÷ 60 = 0.75 hours. So 2 hours 45 minutes = 2.75 decimal hours. The calculator does this automatically and shows both formats.

How do I calculate hours worked for payroll?

Enter your start time (clock-in) and end time (clock-out) for each shift. The decimal hours result can be directly multiplied by your hourly rate. For example, 7.5 hours × $20/hr = $150.

What is ISO 8601 duration format?

ISO 8601 duration format uses the pattern P[n]Y[n]M[n]DT[n]H[n]M[n]S. For a time duration, only the time part is used: PT1H30M0S means 1 hour, 30 minutes, 0 seconds. This format is used in APIs, calendars (iCalendar), and programming languages like Java and JavaScript.

How do I calculate the duration of a meeting?

Enter the meeting start time and end time. The result shows the exact duration in hours, minutes, and seconds. For example, a meeting from 14:00 to 15:45 lasts 1 hour 45 minutes (1.75 decimal hours).

Time Duration Calculator

Calculate the duration between two times of day.

Start Time

End Time

Related Tools

Date Difference Online Timer

Reviewed by

Marcus Webb

Software Engineer & Developer Tools Specialist

· BSc Computer Science, University of Washington· Senior Engineer at Cloudflare (2018–2023)· Open-source contributor to Temporal API proposals

About the Time Duration Calculator

Time duration calculation is fundamental to payroll, invoicing, scheduling, and project management. This calculator converts a start and end time into a precise duration in hours, minutes, and seconds — and in decimal hours for direct use in timesheets and billing.

The calculator automatically handles overnight durations: if the end time is earlier than the start time, it assumes the interval crosses midnight and adds 24 hours accordingly. A night shift from 22:00 to 06:00 is correctly calculated as 8 hours, not −16 hours.

Decimal Hours Quick Reference

Hours : Minutes	Decimal Hours	Calculation
1:15	1.25	15 ÷ 60 = 0.25
1:30	1.50	30 ÷ 60 = 0.50
1:45	1.75	45 ÷ 60 = 0.75
7:30	7.50	30 ÷ 60 = 0.50
8:20	8.33	20 ÷ 60 = 0.333…
10:00	10.00	Full hours, no fraction

Common Use Cases

Timesheets & payroll

Calculate exact hours worked per shift. Multiply decimal hours by your hourly rate to get billable or payable amounts without manual arithmetic.

Freelance invoicing

Track time spent on client work. Convert hours:minutes to decimal hours and multiply by your rate. 3 hours 20 minutes at $75/hr = 3.33 × $75 = $250.

Meeting & event duration

Quickly calculate how long a meeting, webinar, or live event ran from its start and end times for records, reporting, or billing.

Night & rotating shifts

Calculate overnight shift durations without manual midnight-crossing math. Enter clock-in and clock-out times and get the exact hours worked.