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Tool: Time Calculator — Add, Subtract Hours, Minutes & Duration (2026) | Printed on:
Time Calculator — Add, Subtract Hours, Minutes & Duration (2026)
Add or subtract time, calculate elapsed duration between clock times, and convert decimal hours for payroll.
Time Calculation Mode
Sexagesimal (Base-60) Time Arithmetic
Transparent mathematical methodology explained in plain English.
Total Seconds = (Days × 86,400) + (Hours × 3,600) + (Minutes × 60) + SecondsConverts all multi-unit time components to uniform seconds, applies arithmetic operations, and re-normalizes into standard days, hours, minutes, and seconds.
Variables Explained:
- 1 Hour: 60 Minutes = 3,600 Seconds.
- 1 Day: 24 Hours = 1,440 Minutes = 86,400 Seconds.
- Decimal Hours: Hours + (Minutes / 60) + (Seconds / 3600).
Adding Work Shift Times (5h 45m + 3h 35m)
Calculating total combined work hours with base-60 carryover.
- Add minutes: 45m + 35m = 80 minutes.
- Extract full hours from minutes: 80 ÷ 60 = 1 hour with 20 minutes remaining.
- Add hours: 5h + 3h + 1h (carried over) = 9 hours.
- Convert to decimal for payroll: 9 + (20 / 60) = 9.333 decimal hours.
Frequently Asked Questions: Time Calculator
Click any question below to expand quick answers, formulas, and expert tips.
How do I add hours and minutes together?
Add the minutes column first. If the sum reaches or exceeds 60, divide by 60 to find the whole hours to carry over, keeping the remainder as minutes. Then add all hours together plus any carried-over hours.
How do I convert hours and minutes to decimal hours for payroll?
Keep the whole hours as the integer and divide the minutes by 60. For example, 7 hours and 45 minutes equals 7 + (45 / 60) = 7.75 decimal hours.
Can this time calculator calculate elapsed time across midnight?
Yes! When calculating duration between clock times, if the end time is earlier than the start time (e.g., 10:00 PM to 6:30 AM), the calculator automatically computes the overnight transition across midnight (8 hours, 30 minutes).
How do I subtract one time from another?
Subtract minutes from minutes and hours from hours. If the subtracted minutes exceed the starting minutes, borrow 1 hour (60 minutes) from the hours column before subtracting.
How do you convert decimal hours back to minutes?
Multiply the decimal portion by 60. For example, 0.4 hours × 60 = 24 minutes, so 8.4 hours is 8 hours and 24 minutes.
What is the difference between 12-hour AM/PM and 24-hour military time?
12-hour time uses AM (midnight to noon) and PM (noon to midnight). 24-hour military time runs continuously from 00:00 to 23:59 without AM/PM. For times past noon, add 12 to the standard hour (e.g., 3:15 PM = 15:15).
How do I calculate total work hours with unpaid lunch breaks?
Calculate total elapsed clock time from shift start to shift end, then subtract your unpaid break duration. For example, 8:00 AM to 5:00 PM (9 hours) minus a 45-minute lunch break leaves 8 hours and 15 minutes (8.25 billable hours).
How many seconds are in an hour and a day?
One minute has 60 seconds, one hour has 3,600 seconds (60 × 60), and one standard 24-hour day has 86,400 seconds (24 × 3,600).