Time Calculator
Add, subtract, and compare time durations in hours, minutes, seconds, days, and weeks.
Time inputs
Results are calculated instantly in your browser.
Total duration
7 hr 45 min
Difference between the start and end time.
End time
5:00 PM
No midnight crossing for this calculation.
Total hours
7.75
Duration as decimal hours.
Total minutes
465
Useful for schedules and timers.
Total seconds
27,900
Base unit used for precise arithmetic.
Work-hours equivalent
0.97 days
Based on an 8-hour workday.
Insights
Time calculation insights
Main result
The time between 9:15 AM and 5:00 PM is 7 hr 45 min.
Minutes equivalent
This duration equals 465 minutes.
Midnight handling
No midnight crossing for this calculation.
Breakdown
Time duration breakdown
Readable duration
7 hr 45 min
Weeks, days, hours, minutes, and seconds.
Hours
7.75
Useful for payroll, billing, and planning.
Minutes
465
Useful for timers, meetings, and schedules.
Seconds
27,900
Useful for precise timing.
Days
0.32
Duration expressed as calendar days.
Weeks
0.05
Duration expressed as seven-day weeks.
Modes
Add vs subtract time
Add time
Use add time when you know a start point and a length of time. The calculator converts the duration to seconds, adds it to the clock time, and wraps around after 24:00 when needed.
Subtract time
Use subtract time to work backwards from a deadline, departure, appointment, or timer end. This is helpful for finding when to start preparation or leave.
Elapsed time
Use elapsed time when both clock times are known. If the end time is earlier than the start time, the calculator treats it as an overnight interval.
Units
Time units explained
Seconds to minutes
Seconds are the smallest unit shown in this calculator. Every 60 seconds becomes 1 minute, so 90 seconds is 1 minute 30 seconds.
Minutes to hours
Every 60 minutes becomes 1 hour. Decimal hours are useful for billing, while hours and minutes are easier for schedules.
Hours to days
A full clock day has 24 hours. When add or subtract results pass midnight, the clock display wraps into the next or previous day.
Days to weeks
Weeks are counted as seven-day blocks. This is useful for longer countdowns, event planning, and project timelines.
Time arithmetic is easier when everything is temporarily converted into seconds. The calculator then converts the answer back into readable weeks, days, hours, minutes, and seconds so the result is both precise and easy to understand.
Concepts
Clock time vs duration time
Clock time
Clock time is a position on a 24-hour cycle, such as 09:15 or 5:00 PM. It can be shown in 12-hour or 24-hour format without changing the calculation.
Duration
Duration is a length of time, such as 2 hours 15 minutes. Durations can be added to clock times, subtracted from clock times, or compared as totals.
Examples
Work hours and scheduling examples
Shift length
Calculate the full clock-in to clock-out span first, then subtract unpaid breaks separately for a cleaner timesheet estimate.
Meeting duration
Use elapsed mode to compare planned and actual meeting length, especially when sessions cross lunch or midnight.
Travel time
Add travel time, check-in time, and buffer minutes to work backwards from an arrival deadline.
Break deductions
Subtract breaks, waiting periods, or setup time from a longer block to find productive time.
Methodology
Formula and methodology
Total minutes
Total Minutes = Hours x 60 + MinutesConvert hours into minutes, add remaining minutes, then use the total for comparisons.
Total seconds
Total Seconds = Hours x 3600 + Minutes x 60 + SecondsSeconds are a useful base unit because they avoid rounding during the calculation.
Elapsed time
Elapsed Time = End Time - Start TimeIf the result is negative, add 24 hours to handle midnight crossing.
Add and subtract
Final Time = Start Time +/- DurationConvert the duration to seconds, add or subtract it, then convert back to clock time.
Uses
Common use cases
Payroll and timesheets
Convert clock-in and clock-out times into total hours, minutes, and decimal hours before applying break or overtime rules.
Overnight work shifts
Calculate shifts that start in the evening and finish the next morning without manually adding 24 hours.
School schedules
Compare class periods, revision blocks, exam timings, and activity windows in minutes or hours.
Travel planning
Add journey time, transfer time, boarding buffers, and delays to estimate realistic departure or arrival times.
Workouts
Build interval sessions by adding warm-up, work sets, rest periods, and cooldown time into one total duration.
Cooking timers
Work backwards from serving time by subtracting prep, resting, and baking durations.
Meetings
Check meeting length, compare planned vs actual durations, and convert long sessions into total minutes.
Project planning
Turn focused work blocks into realistic schedules by adding setup time, review time, and breaks.
Event schedules
Create a run-of-show by adding segment lengths and checking whether the plan fits inside the available window.
FAQ
Time calculator questions
Choose add time, enter a start time and duration, then the calculator adds the duration to the clock time and shows the final time.
Related tools