Time Duration Calculator
Find the duration between two times, or add and subtract time intervals.
Result
Enter times and click Calculate
Quick Examples
What Is a Time Duration Calculator?
A time duration calculator measures the elapsed time between two clock times. You provide a start time and an end time, and it returns the duration in hours, minutes, and seconds — along with the total expressed as decimal hours and total minutes, which are useful for payroll, billing, and project tracking.
This tool offers two modes. Between Two Times calculates how long it is from one clock reading to another. Add / Subtract takes a base time and a duration, then tells you what time it will be after adding or subtracting that interval — useful for scheduling, cooking timers, and deadline planning.
How Midnight Crossings Are Handled
When the end time is earlier than the start time, the calculator automatically assumes you mean the next calendar day. For example, entering a start of 10:00 PM and an end of 6:00 AM produces a duration of 8 hours — because 6:00 AM the following morning is 8 hours after 10:00 PM. This makes it straightforward to calculate night shifts, overnight travel times, and any schedule that spans midnight without needing to manually adjust the times.
The maximum span in Between Two Times mode is 23 hours 59 minutes 59 seconds (just under one full day). For durations spanning more than one day, use the Add / Subtract mode and enter the full number of hours.
Understanding Decimal Hours
Decimal hours express a duration as a single number rather than hours and minutes separately. The formula is straightforward:
Decimal hours = H + (M ÷ 60) + (S ÷ 3600)
For example, 2 hours 45 minutes converts to 2 + (45 ÷ 60) = 2.75 decimal hours. This format is used heavily in payroll systems, invoicing, and spreadsheet formulas because it allows simple multiplication — if you earn $30 per hour and worked 7.5 decimal hours, your pay is $225 exactly.
Common Conversions
- 30 minutes = 0.5 hours
- 15 minutes = 0.25 hours
- 45 minutes = 0.75 hours
- 20 minutes = 0.333 hours
- 40 minutes = 0.667 hours
- 90 minutes = 1.5 hours
- 1 hour 15 minutes = 1.25 hours
- 1 hour 45 minutes = 1.75 hours
Common Use Cases
Work Shifts and Payroll
Enter your clock-in and clock-out times to find the exact hours worked. The decimal hours result can be directly multiplied by your hourly rate. If your employer rounds to the nearest quarter-hour, use the minutes total to determine the rounded value manually.
Deducting Break Times
To deduct a lunch break from a work shift, first calculate the full shift duration, then use the Add / Subtract mode to subtract the break time. For example: shift duration is 8 hours 30 minutes, subtract 30 minutes for lunch, leaving 8 hours of billable time.
Travel and Commute Times
Determine exactly how long a journey takes by entering departure and arrival times. The calculator handles overnight travel seamlessly — a train departing at 11:45 PM and arriving at 7:20 AM is correctly shown as 7 hours 35 minutes.
Scheduling and Planning
Use the Add / Subtract mode to calculate end times from a start plus an estimated duration. Enter a meeting start of 2:15 PM and add 1 hour 30 minutes to find that it ends at 3:45 PM. Stack multiple additions to plan a full sequence of events.
Cooking and Recipes
Know that a dish needs to cook for 2 hours 20 minutes from 6:30 PM? Add that duration to find the 8:50 PM finish time so you can plan the rest of the meal around it.
Tips for Accurate Results
- Always enter both times in the same time zone.
- Use 24-hour format (e.g., 14:00 for 2:00 PM) to avoid AM/PM ambiguity — this tool's time inputs work in 24-hour format internally.
- For break deductions, calculate the gross duration first, then use Add / Subtract to remove break time.
- For multi-day durations, combine this tool with the Days Between Dates calculator to handle the date portion separately.
Related Tools
If you work with dates as well as times, the days between dates calculator gives you the exact day count between any two calendar dates. For percentage-based time calculations — such as what percentage of the day has elapsed — try our percentage calculator. And if you need to convert between time units and other measurements, the unit converter handles time conversions including seconds, minutes, hours, days, and weeks.
Frequently Asked Questions
How do I calculate hours between two times?
Enter your start and end time then click Calculate. The result shows the total duration broken into hours, minutes, and seconds, plus the total in decimal hours and total minutes.
How does the calculator handle times that cross midnight?
When the end time is earlier than the start time, the calculator automatically treats the end as being on the next day. A shift from 10:00 PM to 6:00 AM is correctly calculated as 8 hours.
How do I calculate my work shift duration?
Enter your clock-in as the start time and your clock-out as the end time, then click Calculate. Night shifts that cross midnight are handled automatically.
Can I include seconds in the calculation?
Yes. Check "Include Seconds" to reveal seconds fields for both start and end times. The result will include the seconds component in its breakdown.
What are decimal hours?
Decimal hours express duration as a single number: hours + (minutes ÷ 60). For example, 1h 30m = 1.5 decimal hours. This is useful for payroll and billing calculations.
How do I add time to a specific time?
Switch to Add / Subtract mode, enter your base time, set the hours and minutes to add, choose "＋ Add", and click Calculate. The result shows the new time of day.
How do I calculate time for payroll?
Enter clock-in and clock-out times to get decimal hours. Multiply decimal hours by your hourly rate for the pay amount. 7 hours 45 minutes = 7.75 decimal hours.
How do I deduct a lunch break?
First calculate the full shift duration. Then in Add / Subtract mode, set the base time to your total hours in HH:MM, choose Subtract, and enter your break time.
What is the maximum duration this calculator supports?
Between Two Times mode supports up to 23h 59m 59s (just under one full day). For longer spans, use Add / Subtract mode and enter the total hours directly.
Does this calculator adjust for time zones?
No. Enter both times in the same time zone for accurate results. For cross-time-zone calculations, convert to a single time zone first.
How do I convert 155 minutes to hours and minutes?
Divide by 60: 155 ÷ 60 = 2 remainder 35. That's 2 hours 35 minutes. Or use Add / Subtract mode: base time 00:00, add 0h 155m — the result will show 2:35 AM, confirming the breakdown.
What is the difference between elapsed time and clock time?
Clock time is a point in the day (e.g., 3:45 PM). Elapsed time is a duration between two clock times (e.g., 2 hours 15 minutes). This calculator takes clock times and returns elapsed time.