Add or subtract two time durations in hours, minutes, and seconds. Get results in multiple formats including decimal hours and total seconds.
The Add Time Calculator combines or subtracts two time durations expressed in hours, minutes, and seconds.
It is useful anywhere you need to total durations rather than work with clock times: shifts, workouts, cooking steps, travel segments, or study sessions. The calculator handles the carry from seconds to minutes and minutes to hours automatically, then shows the result in several common formats such as H:M:S, decimal hours, total minutes, and total seconds.
That makes it easier to move from a human-readable duration to the format a spreadsheet, timesheet, or billing system expects.
Duration math is simple conceptually but easy to miskey once you have to carry seconds and minutes by hand. Showing the result in both clock-style and decimal-style formats helps when the same total has to move between human reading and software entry.
Total Seconds = (H1×3600 + M1×60 + S1) ± (H2×3600 + M2×60 + S2) Result Hours = floor(Total / 3600) Result Minutes = floor((Total mod 3600) / 60) Result Seconds = Total mod 60 Decimal Hours = Total Seconds / 3600
Result: 4h 15m 0s (4.25 decimal hours)
Adding 2 hours 30 minutes to 1 hour 45 minutes: 30 + 45 = 75 minutes = 1 hour 15 minutes. Plus 2 + 1 = 3 hours. Total: 4 hours 15 minutes = 4.25 decimal hours.
Most payroll and invoicing systems require time in decimal hours, not hours:minutes. Converting 7 hours 23 minutes to 7.383 hours manually is tedious and error-prone. This calculator gives you the exact decimal value for accurate billing and payroll.
Athletes and fitness enthusiasts often need to total their daily workout durations — a 45-minute run plus a 30-minute strength session plus a 15-minute cooldown. The visual comparison bar helps you see the proportion of each activity.
Developers frequently convert between time formats: seconds for Unix timestamps, milliseconds for JavaScript timers, and decimal hours for analytics. The comprehensive conversion table serves as a quick reference for all these formats.
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Decimal hours express time as a fraction of an hour. 4 hours 15 minutes = 4.25 hours. This format is standard for timesheets and billing.
Yes. The calculator supports any total duration and shows the days equivalent when the result exceeds 24 hours.
The calculator reports the absolute difference, so the result stays positive even if the second duration is larger than the first.
Enter each work segment as a separate addition. The decimal hours output is the format most timesheet systems require.
Add the first two, note the result, then use it as Time 1 and add the third duration as Time 2. Repeat for additional durations.
Milliseconds are the standard time unit in programming (JavaScript setTimeout, database timestamps). Developers often need this conversion.