Hours Calculator
Calculate total hours worked between clock-in and clock-out times. Compute weekly hours, overtime, and earnings. Add, subtract, and convert between hours, minutes, and seconds. Perfect for time tracking, payroll calculations, and project planning.
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Hours Calculator – Calculate Hours and Minutes Between Two Times
The Hours Calculator computes the exact number of hours and minutes between a start time and an end time. It handles all the complexity of time arithmetic — including midnight crossings, AM/PM conversions, and decimal hour output for payroll — and delivers an instant result.
Time arithmetic is not as simple as regular subtraction. Subtracting 9:45 AM from 5:15 PM requires borrowing from the hours column (since 15 minutes is less than 45 minutes), then dealing with the 12-hour AM/PM convention. For overnight shifts, you must add 24 hours to the end time before subtracting. The hours calculator handles all of this automatically.
💡 Payroll Tip: Employers typically pay by the decimal hour. A shift from 8:45 AM to 5:15 PM is 8 hours 30 minutes = 8.5 decimal hours. At $20/hr, that is $170.00 — not $160.00 as you'd get if you rounded down to 8 hours.
When to Use the Hours Calculator
💼 Payroll & Timesheet Calculation
Calculate total hours worked each day and week for salary, hourly wage, or contractor billing. Convert to decimal hours for payroll software compatibility.
🏥 Medical & Shift Work
Nurses, doctors, and hospital workers frequently work shifts crossing midnight (e.g., 11 PM to 7 AM). The calculator accurately handles these 8-hour overnight shifts.
📚 Study & Productivity Tracking
Track study sessions, focused work blocks, or project time. Calculate total productive hours across multiple sessions in a day or week.
✈️ Travel & Flight Duration
Calculate the duration of a flight or road trip from departure to arrival. Account for time zone changes by using local times at origin and destination.
🍳 Cooking & Baking Timers
If you put a roast in the oven at 2:45 PM for 3 hours 30 minutes, the calculator tells you it's ready at 6:15 PM — no mental arithmetic needed.
🏋️ Exercise & Training Logs
Log the exact duration of workouts, training sessions, or sports events. Accumulate weekly training hours to track whether you are meeting your fitness goals.
Time Calculation Formulas
There are two common operations: finding the duration between two times, and adding or subtracting a duration from a time.
Formula 1: Duration Between Two Times
If the result is negative (midnight crossing), add 1440 (minutes in a day) to get the correct duration.
Formula 2: Convert to Decimal Hours
Quick Minute-to-Decimal Conversion Reference
| Minutes | Decimal Hours | Minutes | Decimal Hours |
|---|---|---|---|
| 5 | 0.083 | 35 | 0.583 |
| 10 | 0.167 | 40 | 0.667 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.333 | 50 | 0.833 |
| 30 | 0.5 | 55 | 0.917 |
Step-by-Step Calculation Guide
Enter the Start Time
Input the time the work or activity began, using the 12-hour (AM/PM) or 24-hour (military) format. 9:00 AM = 09:00; 2:30 PM = 14:30 in 24-hour format.
Enter the End Time
Input the time the activity ended. For overnight shifts (e.g., starting at 10 PM and ending at 6 AM), the calculator automatically adds 24 hours to the end time to handle the midnight crossover.
Subtract Break Time (If Applicable)
For work hours calculations, enter any unpaid break time (e.g., a 30-minute unpaid lunch). This is subtracted from the gross hours to give net paid hours.
Read Hours and Minutes
The primary output is hours and minutes (e.g., 8 hours 30 minutes). This is the most intuitive format for daily scheduling and planning.
Use Decimal Hours for Payroll
For payroll, multiply decimal hours by your hourly rate. Example: 8.5 hours × $22/hour = $187.00. This avoids fractional-minute rounding errors in pay calculations.
Worked Examples
Given:
- • Start Time: 8:45 AM
- • End Time: 5:15 PM
- • Break: 30 minutes (unpaid lunch)
Solution:
End in minutes: 17×60+15 = 1035 min
Start in minutes: 8×60+45 = 525 min
Gross duration: 1035 − 525 = 510 min = 8h 30min
Less break: 510 − 30 = 480 min
Net hours: 8 hours 0 minutes = 8.0 decimal hours
At $25/hour, gross pay = $200.00 for this 8-hour shift (after the 30-minute unpaid break).
Given:
- • Start Time: 10:00 PM
- • End Time: 6:00 AM (next day)
- • Break: None
Solution:
End time + 24h = 6:00 AM + 24h = 30:00 (30 hours from midnight reference)
Start: 22:00
Duration: 30:00 − 22:00 = 8 hours 0 minutes
Overnight shifts always span midnight — the calculator handles this by adding 24 hours to the end time when it's earlier than the start time.
Given:
- • Start Time: 2:45 PM
- • Duration to add: 3 hours 30 minutes
Solution:
Start: 2:45 PM = 14:45
Add 3 hours: 14:45 + 3:00 = 17:45
Add 30 minutes: 17:45 + 0:30 = 18:15
Result: 6:15 PM
If you put food in the oven at 2:45 PM for 3 hours 30 minutes, it's ready at 6:15 PM.
Given:
- • Mon: 8h 00min
- • Tue: 7h 45min
- • Wed: 8h 30min
- • Thu: 8h 15min
- • Fri: 7h 30min
Solution:
Total minutes: 480+465+510+495+450 = 2400 minutes
Total hours: 2400 ÷ 60 = 40 hours 0 minutes
Decimal: 40.0 hours
This employee worked exactly 40 hours this week — no overtime. At the 41st hour, overtime pay (typically 1.5×) would begin.
Given:
- • Departure: 11:30 AM (New York, Eastern)
- • Arrival: 2:45 PM (London, next day, BST = Eastern+5)
Solution:
Convert arrival to Eastern: 2:45 PM BST − 5h = 9:45 AM Eastern (next day)
Add 24h for next day: 9:45 AM + 24h = 33:45 Eastern reference
Start: 11:30 AM = 11:30
Duration: 33:45 − 11:30 = 22 hours 15 minutes
Always convert to the same time zone before calculating flight durations to avoid errors from time zone differences.
Common Mistakes to Avoid
Treating minutes like decimal numbers
1 hour 30 minutes ≠ 1.30 hours. It is 1.5 hours. Minutes must be divided by 60 to convert to decimal: 30 ÷ 60 = 0.5.
Forgetting to subtract break time for payroll
A 30-minute unpaid lunch means an 8-hour shift is actually 7.5 paid hours. Forgetting to subtract break time leads to paying for time not worked.
Not accounting for midnight crossings
A shift from 9 PM to 5 AM is 8 hours, not −16 hours. When end time is before start time on a clock, add 24 hours to the end time before subtracting.
Mixing 12-hour and 24-hour formats
Entering 8:00 PM as 8:00 (confusing it with 8:00 AM) will produce a negative duration. Always confirm AM/PM or use 24-hour format consistently.
Ignoring overtime thresholds in total hours calculations
In many jurisdictions, hours over 8 per day or 40 per week qualify for overtime pay (typically 1.5× the regular rate). Track daily and weekly totals separately.
Tips and Best Practices
- ✓Always use decimal hours for payroll calculations. Payroll software and most wage calculations require decimal hours, not hours:minutes. Convert with Minutes ÷ 60.
- ✓Track breaks separately from work time. For compliance with labor laws, document break times explicitly. Many jurisdictions require a 30-minute unpaid break for shifts over 6 hours.
- ✓Use 24-hour (military) time to avoid AM/PM confusion. In healthcare, military, and international contexts, 24-hour time eliminates the ambiguity of AM/PM, especially useful when entering times near midnight or noon.
- ✓Round to the nearest quarter-hour for simplified payroll. Many employers round shift times to the nearest 15 minutes (e.g., 8:52 AM rounds to 8:45 or 9:00). Confirm your employer's rounding policy.
- ✓Log hours daily, not weekly. Entering daily hours as you work prevents errors from forgotten start/end times. A week of daily logs is far more accurate than reconstructing the week from memory on Friday.
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Conclusion
The Hours Calculator brings precision to time arithmetic — a task that is far more error-prone than it looks. Whether you are calculating a daily work shift, an overnight hospital rotation, a weekly total for payroll, or the duration of a long-haul flight, the calculator handles AM/PM conversion, midnight crossings, and break deductions automatically.
The most important takeaway for payroll use is the decimal hours conversion: minutes are not the same as hundredths of an hour. 30 minutes = 0.5 hours, not 0.30 hours. Getting this right ensures accurate pay for every shift.
Disclaimer: This calculator provides mathematical time calculations. For payroll and labor compliance, consult your employer's policies and applicable labor laws. Overtime rules, break requirements, and rounding policies vary by jurisdiction and employer.
Frequently Asked Questions
How do you calculate hours between two times?
Convert both times to total minutes from midnight, subtract start from end. If negative (overnight shift), add 1440. Divide by 60 for hours.
How do you convert minutes to decimal hours?
Divide minutes by 60. Example: 45 minutes ÷ 60 = 0.75 decimal hours. So 3 hours 45 minutes = 3.75 decimal hours.
How do you handle shifts crossing midnight?
Add 24 hours to the end time before subtracting. Example: End at 6 AM, Start at 10 PM → (6+24) − 22 = 8 hours.
How do I calculate weekly total hours?
Sum all daily minutes worked, subtract break times, then divide by 60 for total hours.
What is 7 hours 45 minutes in decimal?
7 + (45÷60) = 7 + 0.75 = 7.75 decimal hours.
How do I add hours and minutes together?
Add minutes first. If the result exceeds 59, carry 1 hour for every 60 minutes. Then add the hours.
What is the difference between hours worked and decimal hours?
Hours and minutes (e.g., 8h 30min) is the natural time format. Decimal hours (e.g., 8.5) is used for payroll calculations.
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