Date & Time
Age, duration & timezone calculators
Time Duration Calculator
Hours and minutes between two times, shown as H:MM, total minutes and decimal hours (for timesheets). Overnight-safe — a 22:00 → 06:00 shift reads 8 hours, not −16 — with an unpaid-break deduction. Pure clock math, computed entirely in your browser. Accurate, instant and free — for United States.
What these mean:
8h 30m (8.5 decimal hours).
Duration
8h 30m
Decimal hours
8.5
Total minutes
510 min
09:00 → 17:30 is 8h 30m — 8.5 decimal hours.
Overnight / cross-midnight
Payroll rounding
How we calculate
How we calculate this
Reviewed by Reckonist Editorial · Last reviewed July 2026. Figures follow the methods and sources set out in our editorial standards.
Clock math in minutes; overnight adds 24 hours when the end is before the start. Pure clock time — DST only applies if you use full dates.
ISO-8601 times · decimal hours
Take it further: total a full shift with breaks in the Time Card Calculator, or count whole days with the Date Difference Calculator.
Hours between two times
The core case is the elapsed time between a start and an end time on a 24-hour clock. Both are converted to minutes since midnight and subtracted, then the result is shown three ways — H:MM, total minutes, and decimal hours — plus overnight and break handling.
Elapsed time
minutes since midnight
duration = end − start (minutes) · H:MM = ⌊m/60⌋ : m mod 60
Pure clock math — no dates, so a duration is stable regardless of your time zone.
Decimal hours
for timesheets
decimal hours = minutes ÷ 60
510 minutes ÷ 60 = 8.5 h — the figure payroll multiplies by an hourly rate.
- 1Subtract the times: 1,050 − 540 = 510 minutes.
- 2Convert: 510 min = 8h 30m = 8.5 decimal hours.
Overnight — the cross-midnight case
When the end time is earlier than the start — a graveyard shift like 22:00 → 06:00 — the interval crosses midnight. Turn on Overnight and the calculator adds 24 hours before subtracting, so the result is 8 hours, not −16. This is the single most common bug in plain time-subtractors.
Worked example · 22:00 → 06:00
Decimal hours vs H:MM
H:MM is how we read a clock (8h 30m), but decimal hours (8.5) is what payroll multiplies by a rate. The conversion is just minutes ÷ 60: 15 minutes is 0.25 h, 20 minutes is 0.33 h, 45 minutes is 0.75 h. The tool shows both so you never have to convert by hand.
Common conversions
Subtracting unpaid breaks
Enter an unpaid break in minutes and it is subtracted from the elapsed time. A 09:00 → 17:30 span is 8h 30m; after a 30-minute lunch it is 8h 00m (480 minutes). The result is clamped at zero, so an over-long break can never produce a negative duration.
Worked example · 30-min break
Payroll-increment rounding
Decimal hours alone aren’t what payroll runs on — most systems round each entry to a fixed increment: the quarter-hour(0.25 h / 15 min, the “7-minute rule”), the tenth(0.1 h / 6 min), or whole minutes. The increment changes the paid total, so it’s worth knowing which one your employer uses.
Worked example · 8h 23m
Frequently asked questions
Convert both times to minutes since midnight and subtract: 17:30 is 1,050 minutes, 09:00 is 540, so the gap is 510 minutes — 8 hours 30 minutes, or 8.5 decimal hours. The calculator shows all three (H:MM, total minutes and decimal hours) at once.
When the end time is earlier than the start, turn on Overnight and the calculator adds 24 hours before subtracting: 06:00 becomes 30:00, minus 22:00, is 8 hours. Without the overnight flag a plain subtraction would give −16 hours, which is the classic bug this tool avoids.
Divide the total minutes by 60: 510 minutes ÷ 60 = 8.5 decimal hours. Decimal hours are what most timesheets and payroll systems expect, because you multiply them directly by an hourly rate. 8h 15m is 8.25 h, 8h 45m is 8.75 h.
Enter the unpaid break in minutes and it is subtracted from the elapsed time. A 09:00 → 17:30 span is 8h 30m, and after a 30-minute lunch it is 8h 00m (480 minutes). The result never drops below zero.
Many payroll systems round each entry to a fixed increment — most often the quarter-hour (0.25 h / 15 min) or the tenth (0.1 h / 6 min). 8h 23m is 8.38 decimal hours, which rounds to 8.50 h at the quarter-hour or 8.40 h at tenths. Check which increment your employer uses, because it changes the paid total.
Not for pure clock times. This calculator works in minutes since midnight, so it never crosses a real DST boundary. DST only matters when you compute a duration across full calendar dates and time zones — for that, use a date-and-time difference instead.
Method & references
Methodology: both times are parsed to minutes since midnight; the duration is end − start (plus 24 hours when Overnight is on so a cross-midnight shift reads positive); an optional break is subtracted and the result is clamped at zero; outputs are H:MM (⌊min/60⌋ : min mod 60), total minutes, and decimal hours (minutes ÷ 60). Pure clock math — DST only applies when full dates and time zones are used. All calculations run client-side and nothing is stored.
Cross-links
How we calculate this
Reviewed by Reckonist Editorial · Last reviewed July 2026. Figures follow the methods and sources set out in our editorial standards.
Clock math in minutes; overnight adds 24 hours when the end is before the start. Pure clock time — DST only applies if you use full dates. Reference: ISO-8601 times.
Keep going
Same-category tools follow this colour; a cross-category link keeps its own.