How do I add or subtract hours and minutes?

Enter one duration per line in Add / subtract mode. For 1:45 plus 0:52:30 plus 2:10 minus a 15-minute break, enter 1:45, 0:52:30, 2:10 and -15m. The total is 4:32:30, or 4.54 decimal hours and 272.5 minutes. Hours do not wrap at 24: a 25-hour duration remains 25:00:00. The finishing clock wraps separately when a start is supplied.

What time formats can I type?

Colon form is always hours:minutes or hours:minutes:seconds. A 30-second clip is 0:00:30 or 30s, not 0:30. Unit form accepts hours, minutes and seconds, including 1h30m20s, 2.5h and 1.5 minutes. A plain number means minutes. One leading plus or minus applies to the whole line. Anything after two spaces, a tab or a # is a note, so use single spaces between unit terms. Days, weeks, frames, exponent notation and mathematical expressions are not duration formats here.

Can the result be negative?

Yes. In addition mode, -1h subtracts an hour. A 0:30 duration minus 1:00 gives -0:30:00, -0.50 decimal hours and -30 minutes. Nothing is clamped to zero. In Average mode a negative line is a negative observation, so 1h and -1h average to zero; a break subtracted from a shift is usually an addition-mode task.

How do I calculate the average of multiple time durations?

Choose Average and enter the durations one per line. 1m 30s, 2m and 1m total 4m 30s; dividing by three gives a mean of 1m 30s. Each line is first rounded to a whole second, then the arithmetic mean is rounded to the nearest whole second, with halves away from zero. Blank lines and notes are excluded. Invalid lines are excluded from the clearly labelled preview; correct them before treating the result as complete. This averages duration measurements, not times of day, pace over unequal distances, weighted values or medians.

How do I convert hours and minutes to decimal hours or minutes?

Divide minutes by 60 and add the hours: 4:30 is 4.5 hours, displayed as 4.50. 4:20 displays 4.33 hours. Decimal hours round to two places; decimal minutes round to at most two places. For example, 20s displays 0.33 minutes even though the exact fraction is one third. The h:mm:ss result retains whole seconds. Choose h:mm to drop the seconds from the display without rounding them into another minute.

How do I convert minutes or seconds into hours, minutes and seconds?

Enter 90 for ninety minutes or 5400s for 5,400 seconds; both display 1:30:00. For 3,665 seconds, enter 3665s and read 1:01:05. For minutes and seconds such as 3m 25s, use unit letters or 0:03:25; a two-part colon duration is hours and minutes. The same result is shown as decimal hours and rounded decimal minutes.

Can I add time to an AM/PM or military-time start?

The optional Start from field accepts 09:00, 17:30, 9am and 5:30 PM, with optional seconds in a colon form. 12 AM is midnight and 12 PM is noon. Choose 24 hour or AM / PM for the finishing clock. A 23:30 start plus 1h ends at 00:30 the next day, or 12:30 AM. A negative duration runs backwards and marks the day before when needed. To find the interval between two clock readings, use the hours calculator rather than entering them as duration lines.

What time will my movie end?

Use the Movie end time page. Enter the supplied runtime and any known trailer or interval duration as separate lines, then supply the start time. Starting at 7 PM with 2h and 20m gives 9:20 PM. Trailer duration is your input, not a cinema forecast. There is no film-title lookup, showtime feed, film-footage calculation or frame-rate timing.

Does this calculate date intervals, time cards or travel arrival times?

Time Calculator does arithmetic on supplied durations and one clock reading. Hours Calculator handles clock-in/clock-out shifts and breaks. Duration Calculator handles two dates and times, including elapsed hours across local daylight-saving changes. Meeting Planner compares selected cities. This clock-only result has no date, timezone, route, distance, speed or live travel data, so it cannot estimate a journey or adjust for a clock change.

How does rounding and the numeric range work?

Each duration line is rounded once to the nearest whole second, with a half second rounding up in magnitude. Decimal terms are accumulated before rounding, so 0.4s 0.4s becomes one second. Each accepted duration and a displayed signed total can have a magnitude up to 1,000,000,000,000 seconds. An out-of-range total is refused rather than shown approximately. Average mode can still compute a valid mean from individually accepted entries. Errors name the affected line or total; valid lines remain visible as a partial preview.

Are my entries saved, and can I copy the calculation?

Intentional edits save the list, start time, modes and displays on this device when browser storage is available. Loading defaults or restoring a saved list does not overwrite it or count as a completed calculation. The Average and Movie pages apply their stated initial presets before restored settings. Copy puts the current calculation or a displayed value on the native clipboard. No input is uploaded; if storage or copying is blocked, the tool stays usable and the copy message explains the fallback.

Time Calculator

Add and subtract hours, minutes and seconds, with the result shown as a clock, decimal hours and minutes. Type durations one per line: 1:45 means one hour and 45 minutes, 0:00:30 means thirty seconds, 90 means ninety minutes, and 2.5h means two and a half hours. A leading minus subtracts a duration; two spaces or a # introduce a note. Average mode finds the arithmetic mean of the signed entries. Supply a 24-hour or AM/PM start time to calculate when the selected total or mean finishes, including midnight crossings. For a time card of clock-in and clock-out times with breaks and rounding, use the hours calculator; for the time between two dates, use the duration calculator.

Entries0 lines · Enter adds a line

Durations to add up, one per line

Total0:00:00One duration per line: 1:45, 1h 30m, or 90 for minutes

Calculation

Format

Start from

End time: needs a start

Clock display

One duration per line. Write 1:45 or 1:45:00, 1h 30m 20s, 90 for ninety minutes, or 2.5h. A leading minus takes the line off the total, and anything after two spaces or a # is a note that is kept but not counted.

This page adds, subtracts or averages lengths of time. For clock-in and clock-out times with breaks and payroll rounding, use the hours calculator; for the time between two dates, the duration calculator; to compare clock times in different cities, use the meeting planner. Every line is parsed to whole seconds and the total is exact; decimal hours are rounded to two places. Adding to a start time wraps past midnight and says so. Decimal minutes are rounded to at most two places.

Average durations · Movie end time

Common questions

How do I add or subtract hours and minutes?: Enter one duration per line in Add / subtract mode. For 1:45 plus 0:52:30 plus 2:10 minus a 15-minute break, enter 1:45, 0:52:30, 2:10 and -15m. The total is 4:32:30, or 4.54 decimal hours and 272.5 minutes. Hours do not wrap at 24: a 25-hour duration remains 25:00:00. The finishing clock wraps separately when a start is supplied.
What time formats can I type?: Colon form is always hours:minutes or hours:minutes:seconds. A 30-second clip is 0:00:30 or 30s, not 0:30. Unit form accepts hours, minutes and seconds, including 1h30m20s, 2.5h and 1.5 minutes. A plain number means minutes. One leading plus or minus applies to the whole line. Anything after two spaces, a tab or a # is a note, so use single spaces between unit terms. Days, weeks, frames, exponent notation and mathematical expressions are not duration formats here.
Can the result be negative?: Yes. In addition mode, -1h subtracts an hour. A 0:30 duration minus 1:00 gives -0:30:00, -0.50 decimal hours and -30 minutes. Nothing is clamped to zero. In Average mode a negative line is a negative observation, so 1h and -1h average to zero; a break subtracted from a shift is usually an addition-mode task.
How do I calculate the average of multiple time durations?: Choose Average and enter the durations one per line. 1m 30s, 2m and 1m total 4m 30s; dividing by three gives a mean of 1m 30s. Each line is first rounded to a whole second, then the arithmetic mean is rounded to the nearest whole second, with halves away from zero. Blank lines and notes are excluded. Invalid lines are excluded from the clearly labelled preview; correct them before treating the result as complete. This averages duration measurements, not times of day, pace over unequal distances, weighted values or medians.
How do I convert hours and minutes to decimal hours or minutes?: Divide minutes by 60 and add the hours: 4:30 is 4.5 hours, displayed as 4.50. 4:20 displays 4.33 hours. Decimal hours round to two places; decimal minutes round to at most two places. For example, 20s displays 0.33 minutes even though the exact fraction is one third. The h:mm:ss result retains whole seconds. Choose h:mm to drop the seconds from the display without rounding them into another minute.
How do I convert minutes or seconds into hours, minutes and seconds?: Enter 90 for ninety minutes or 5400s for 5,400 seconds; both display 1:30:00. For 3,665 seconds, enter 3665s and read 1:01:05. For minutes and seconds such as 3m 25s, use unit letters or 0:03:25; a two-part colon duration is hours and minutes. The same result is shown as decimal hours and rounded decimal minutes.
Can I add time to an AM/PM or military-time start?: The optional Start from field accepts 09:00, 17:30, 9am and 5:30 PM, with optional seconds in a colon form. 12 AM is midnight and 12 PM is noon. Choose 24 hour or AM / PM for the finishing clock. A 23:30 start plus 1h ends at 00:30 the next day, or 12:30 AM. A negative duration runs backwards and marks the day before when needed. To find the interval between two clock readings, use the hours calculator rather than entering them as duration lines.
What time will my movie end?: Use the Movie end time page. Enter the supplied runtime and any known trailer or interval duration as separate lines, then supply the start time. Starting at 7 PM with 2h and 20m gives 9:20 PM. Trailer duration is your input, not a cinema forecast. There is no film-title lookup, showtime feed, film-footage calculation or frame-rate timing.
Does this calculate date intervals, time cards or travel arrival times?: Time Calculator does arithmetic on supplied durations and one clock reading. Hours Calculator handles clock-in/clock-out shifts and breaks. Duration Calculator handles two dates and times, including elapsed hours across local daylight-saving changes. Meeting Planner compares selected cities. This clock-only result has no date, timezone, route, distance, speed or live travel data, so it cannot estimate a journey or adjust for a clock change.
How does rounding and the numeric range work?: Each duration line is rounded once to the nearest whole second, with a half second rounding up in magnitude. Decimal terms are accumulated before rounding, so 0.4s 0.4s becomes one second. Each accepted duration and a displayed signed total can have a magnitude up to 1,000,000,000,000 seconds. An out-of-range total is refused rather than shown approximately. Average mode can still compute a valid mean from individually accepted entries. Errors name the affected line or total; valid lines remain visible as a partial preview.
Are my entries saved, and can I copy the calculation?: Intentional edits save the list, start time, modes and displays on this device when browser storage is available. Loading defaults or restoring a saved list does not overwrite it or count as a completed calculation. The Average and Movie pages apply their stated initial presets before restored settings. Copy puts the current calculation or a displayed value on the native clipboard. No input is uploaded; if storage or copying is blocked, the tool stays usable and the copy message explains the fallback.

Every line is parsed to whole seconds and the total is exact; decimal hours are rounded to two places. Adding to a start time wraps past midnight and says so.