How to Use Our Time Calculator

This tool is designed to be intuitive, whether you’re finding a duration or performing time arithmetic. It supports both 12-hour (AM/PM) and 24-hour clock formats.

1. To Calculate the Duration Between Two Times

Use this function to find the total elapsed time between a start and end point. This is ideal for calculating work shifts, flight times, or event lengths.

• Start Time: Enter the time when the period began. You can type it in or use the selectors. For example, “9:00 AM” or “15:30”.

• End Time: Enter the time when the period concluded. For convenience, you can click a “Now” button to automatically input the current time (Sunday, August 3, 2025, 12:34 AM).

2. To Add or Subtract a Duration from a Time

Use this function to find a future or past time. For example, “What time will it be in 3 hours and 45 minutes?”

• Start Time: Enter the initial time for your calculation (e.g., “10:00 PM”).

• Operation: Choose whether you want to Add (+) or Subtract (-) a duration.

• Hours / Minutes / Seconds: Input the amount of time you wish to add or subtract.

Understanding Your Results

Time math isn’t always straightforward. Our calculator simplifies it and presents the results in a clear and useful format.

Your Resulting Time Duration

When you calculate the duration between two times, the calculator provides two outputs:

1. Standard Format (HH:MM:SS): This shows the total elapsed time in hours, minutes, and seconds. This is the most common way to express a time duration.

2. Decimal Hours: This format converts the entire duration into a single decimal number. This is extremely useful for business applications, especially for calculating payroll.

Example: Calculating a Work Shift

• Start Time: 8:30 AM

• End Time: 5:15 PM

• Result (Standard): 8 hours, 45 minutes, 0 seconds

• Result (Decimal): 8.75 hours

The Math Behind Time Calculation

Time uses a sexagesimal (base-60) system, which is different from the decimal (base-10) system we use for regular math. This is why you can’t just add and subtract time like normal numbers. The calculator handles this automatically.

When minutes or seconds add up to 60 or more, they “carry over” to the next higher unit.

Concrete Example: You start a task at 10:45 AM and work on it for 50 minutes.

• The calculation is $10:45+00:50$.

• Adding the minutes: $45+50=95$ minutes.

• Since 95 minutes is more than 60, we convert it: $95\text{ minutes}=1\text{ hour and }35\text{ minutes}$.

• Add this to the original hour: $10\text{ hours}+1\text{ hour}=11\text{ hours}$.

• Final Time: 11:35 AM.

Frequently Asked Questions

### How do I calculate my work hours and breaks for a timesheet?

This is one of the most common uses for our calculator. To get an accurate total, you need to calculate your work period and then subtract your unpaid break time.

Concrete Example: You work from 8:00 AM to 4:30 PM with an unpaid 30-minute lunch break.

1. Step 1: Calculate the total time span.

   • Use the “Duration Between Two Times” function.

   • Start Time: 8:00 AM

   • End Time: 4:30 PM

   • Result: 8 hours, 30 minutes.

2. Step 2: Subtract the break time.

   • Use the “Add or Subtract Time” function.

   • Start Time: 8:30:00 (from Step 1)

   • Operation: Subtract (-)

   • Minutes: 30

   • Final Paid Hours: 8 hours, 0 minutes.

How do I convert minutes to decimal hours for payroll?

Payroll systems almost always require hours to be in a decimal format. The conversion is simple, but it’s a common source of errors if done manually. The formula is:

Decimal Hours=60Total Minutes

Our calculator provides this conversion automatically. However, here is a quick reference table for common values:

• 12-Hour Clock: Divides the 24-hour day into two periods: AM (ante meridiem, “before midday”) from midnight to noon, and PM (post meridiem, “after midday”) from noon to midnight.

• 24-Hour Clock: Runs continuously from 00:00 (midnight) to 23:59. It is often called “military time” in the United States.

Our calculator accepts both formats. For example, 1:00 PM is the same as 13:00.

How do I calculate time that crosses midnight, like a night shift?

The calculator handles this automatically. Simply enter the start and end times, and it will correctly calculate the duration even if it spans across two different dates.

Concrete Example: A security shift from 10:00 PM to 6:00 AM the next day.

• Start Time: 10:00 PM

• End Time: 6:00 AM

• The calculator understands this is an 8-hour duration. It calculates the time from 10:00 PM to midnight (2 hours) and adds the time from midnight to 6:00 AM (6 hours).

• Result: 8 hours, 0 minutes.

Can this calculator handle durations longer than 24 hours?

Yes. If the duration between the start and end time exceeds 24 hours, the result will show the total elapsed time. For example, the duration between Monday at 9:00 AM and Tuesday at 11:00 AM is 26 hours. Our tool can also display this as “1 day, 2 hours, 0 minutes.”

How do I add up a list of time durations?

This is useful for totaling hours on a project or adding up segments of a trip. Use the “Add Time” function sequentially.

Concrete Example: Totaling three tasks that took 1h 15m, 2h 30m, and 0h 45m.

1. Start with the first duration: Enter 01:15:00 as the “Start Time”.

2. Add the second duration: Select Add (+) and enter 02:30:00. The result is 03:45:00.

3. Add the third duration: Using the previous result, add 00:45:00.

4. Final Total Time: 04:30:00 (4 hours and 30 minutes).

How do I calculate running pace using this calculator?

Pace is a measure of time per unit of distance. Our calculator can help with the ‘time’ part of the equation.

Concrete Example: You ran 5 miles and want to find your pace per mile.

1. First, use our calculator to find your total run time if needed. Let’s say your total time was 45 minutes and 30 seconds.

2. To find your pace, you need to divide the total time by the distance. This requires converting your time into a single unit (like seconds):

   • $45\text{ minutes}\times 60=2700$ seconds.

   • Total time = $2700+30=2730$ seconds.

3. Divide by distance: $2730\text{ seconds}/5\text{ miles}=546$ seconds per mile.

4. Convert back to minutes and seconds: $546/60=9$ with a remainder of $6$.

5. Your pace is 9 minutes and 6 seconds per mile.

What is Coordinated Universal Time (UTC)?

UTC is the primary time standard by which the world regulates clocks and time. It is a successor to Greenwich Mean Time (GMT) and is the same everywhere in the world, not adjusting for time zones or Daylight Saving Time. While our calculator operates on the local time you input, UTC is the underlying reference for all global timekeeping systems.

Why are there 60 seconds in a minute and 60 minutes in an hour?

This system, known as a sexagesimal (base-60) system, dates back to ancient Mesopotamia and the Babylonians around 2000 B.C. They used base-60 for mathematics and astronomy, likely because 60 is divisible by many numbers (1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30), making fractions easier to calculate. This system was passed down through the centuries and remains the global standard for measuring time and angles.

How does this tool differ from a Date Calculator?

• Time Calculator (This Tool): Focuses on smaller units of time—hours, minutes, and seconds. It’s ideal for daily schedules, timesheets, and durations that are typically less than a few days.

• Date Calculator: Focuses on larger units—days, weeks, months, and years. It’s used for finding the duration between two calendar dates or calculating a future date for a deadline.

Take the Next Step

Now that you’ve calculated your time, put that information to work.

• Calculating hours for payroll? Once you have the decimal hours, use our Hourly Paycheck Calculator to estimate your earnings.

• If your time calculation spans several months or even years, the right tool for the job is our Date Calculator.

• Planning a workout? After calculating your target duration, see how many calories you might burn with our Activity Calorie Burn Calculator.