Hours

Hours and minutes between two times.

Duration
8.50h
8
Hours
30
Minutes
510
Total min

How to Use the Hours Calculator

  1. Enter the start time and end time for your first shift using the time input fields (12-hour or 24-hour format).
  2. If a shift crosses midnight, ensure you mark the end time as belonging to the next day so the calculator computes the duration correctly.
  3. Click 'Add Shift' to add additional rows for each subsequent shift or work period.
  4. Repeat steps 1–3 for every shift you want to include in your total.
  5. Click 'Calculate' to instantly see the total hours and minutes worked across all entered shifts.
  6. Review the per-shift breakdown and the grand total displayed in hours and minutes (e.g., 9 h 45 min).

How the Hours Calculator Computes Total Time

Total Hours = Σ (End_i − Start_i)  for i = 1 to n

Where each duration = (End_i − Start_i) in hours, and all durations are summed.

For each shift, the calculator finds the duration by subtracting the start time from the end time. All individual shift durations are then summed to produce the grand total.

Times are converted to decimal hours (or minutes) before arithmetic to ensure accuracy across midnight crossings and mixed units.

  • End_i — The end time of shift i, expressed in 24-hour (or converted decimal) format.
  • Start_i — The start time of shift i, expressed in 24-hour (or converted decimal) format.
  • n — The total number of shifts being summed.
  • Total Hours — The cumulative sum of all individual shift durations, expressed in hours and minutes.

Worked Example: Three-Day Work Week

Shift 1: 9:00 AM – 5:30 PM (Monday) Shift 2: 7:45 AM – 3:15 PM (Wednesday) Shift 3: 12:00 PM – 8:00 PM (Friday)
Shift 1 duration: 5:30 PM − 9:00 AM = 8 hours 30 minutes = 8.50 h
Shift 2 duration: 3:15 PM − 7:45 AM = 7 hours 30 minutes = 7.50 h
Shift 3 duration: 8:00 PM − 12:00 PM = 8 hours 0 minutes = 8.00 h

Total = 8.50 + 7.50 + 8.00 = 24.00 hours

Result: Total hours worked: 24 hours 0 minutes (24.00 decimal hours)

What Your Result Means

The result shows your total hours worked expressed in both hours-and-minutes format (e.g., 24 h 0 min) and as a decimal (e.g., 24.00 h). The decimal format is especially useful for payroll calculations where you multiply total hours by an hourly wage. If any shift runs past midnight, those minutes/hours are still counted correctly as long as the end time is properly set to the next calendar day.

Understanding Hours

Understanding Hours Calculation for Shifts

Why Decimal Hours Matter

When computing pay, most payroll systems use decimal hours rather than hours-and-minutes. For example, 7 hours and 30 minutes is expressed as 7.50 decimal hours. To convert minutes to a decimal, divide the minutes by 60 (e.g., 30 ÷ 60 = 0.50).

Handling Overnight Shifts

If a shift starts at 10:00 PM and ends at 6:00 AM, the duration is 8 hours. The calculator handles this by treating the end time as belonging to the following day (i.e., adding 24 hours to the end time before subtracting the start time when end < start).

Paid vs. Unpaid Breaks

This calculator sums the raw time between start and end. If your workplace deducts unpaid break time, you should either split the shift around the break (enter separate sub-shifts) or subtract the break duration from the total manually.

Weekly Hour Tracking

In the United States, the Fair Labor Standards Act (FLSA) generally requires overtime pay for hours worked beyond 40 in a single workweek. Accurately summing your weekly shift hours helps you identify when overtime thresholds are crossed.

Rounding Conventions

Some employers round shift times to the nearest quarter-hour (15 minutes) or tenth-of-an-hour (6 minutes). Check your employer's rounding policy and apply it to your inputs for the most accurate payroll estimate.

Common Mistakes

  • Entering times in the wrong AM/PM slot, causing a negative or wildly inflated duration (e.g., confusing 12:00 PM with 12:00 AM).
  • Forgetting to mark overnight shifts as crossing into the next day, resulting in a negative duration calculation.
  • Including unpaid break time inside a single shift entry instead of splitting the shift or subtracting break minutes separately.
  • Using 12-hour clock format inconsistently — mixing up 12:00 PM (noon) and 12:00 AM (midnight) is the most common single-point error.
  • Summing hours-and-minutes directly as if they were decimal numbers (e.g., treating 7:45 + 8:30 as 15:75 instead of 16:15).

Common Questions About Hours

How do I convert hours and minutes to decimal hours?

Divide the minutes portion by 60 and add it to the hours. For example, 3 hours 45 minutes = 3 + (45 ÷ 60) = 3.75 decimal hours.

How many hours is a standard full-time work week in the US?

The standard full-time workweek in the United States is 40 hours, as defined by the Fair Labor Standards Act. Hours beyond 40 in a workweek generally qualify for overtime pay at 1.5× the regular rate for non-exempt employees.

How do I calculate total pay from hours worked?

Multiply your total decimal hours by your hourly wage. For example, 38.5 hours × $18.00/hr = $693.00 gross pay before taxes and deductions.

What if I work different hourly rates on different shifts?

Calculate each shift's duration separately, then multiply each duration by its respective rate and sum the results. For example, 8 h at $15 + 4 h at $22.50 = $120 + $90 = $210 total.

Frequently Asked Questions

Can this calculator handle overnight shifts that cross midnight?

Yes. When the end time is earlier than the start time (e.g., start 10:00 PM, end 6:00 AM), the calculator automatically adds 24 hours to the end time before computing the duration, giving the correct 8-hour result.

How do I account for unpaid lunch breaks?

The simplest approach is to split a shift into two entries — one before the break and one after. For example, a 9 AM–5 PM shift with a 30-minute unpaid lunch would be entered as 9:00 AM–12:30 PM and 1:00 PM–5:00 PM, totaling 7.5 hours.

What is the difference between decimal hours and hours:minutes format?

Hours:minutes format shows time as 7 h 30 min. Decimal hours express the same duration as 7.50 h by dividing minutes by 60. Decimal format is required for most payroll multiplication (hours × wage rate).

How many shifts can I add?

You can add as many shifts as needed. The calculator dynamically adds rows so you can log an entire week, pay period, or project without limitation.

Can I use this calculator for freelance billing?

Absolutely. Enter the start and end times of each client session, and the total gives you the billable hours to multiply by your hourly rate.

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