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Time calculator: add and subtract hours and minutes

Add and subtract hours, minutes and seconds from a list of durations, with the total as H:MM:SS, decimal hours, minutes and seconds.

Aktualisiert Geprüfte Beispiele: 4

H:MM:SS or H:MM, or 2h 15m, 90 min, 1.5 h. Start a line with − to subtract it.
Ausprobieren
Total
3 h 35 min 45 s
Total: 3 h 35 min 45 s
Total as H:MM:SS
3:35:45
Decimal hours
3.5958h
Total minutes
215.75min
Total seconds
12,945s

The 3 entries add up to 3:35:45 (H:MM:SS), which is 3.5958 hours or 215.75 minutes.

Each entry in hours

Line 11:45:30Line 22:20:15Line 3−30:00
Line by line Zeilen: 3
LineEntrySecondsRunning total
11:45:306,3301:45:30
22:20:158,4154:05:45
3- 0:30:00−1,8003:35:45
So wird gerechnet S

  1. Convert each entry to seconds

    6,330+8,415−1,800=12,945 s6{,}330 + 8{,}415 - 1{,}800 = 12{,}945\ \text{s}

    H:MM:SS → 3600 × H + 60 × MM + SS.

  2. Back to hours, minutes and seconds

    12,945 s = 3:35:45

  3. Decimal hours

    12,9453600=3.595833 h\frac{12{,}945}{3600} = 3.595833\ \text{h}

Über Time calculator: add and subtract hours and minutes

Each line is converted to seconds (3,600 × hours + 60 × minutes + seconds), lines that start with a minus sign are subtracted, and the sum is turned back into hours, minutes and seconds. Entries can be written as H:MM:SS, H:MM, 2h 15m, 90 min or 1.5 h. The total is a duration, not a time of day, so 23:59:59 plus one second gives 24:00:00 rather than wrapping to midnight.

Typical uses are adding up timesheet entries, video clip lengths, lap splits and flight legs. The default list, 1:45:30 plus 2:20:15 minus 0:30:00, totals 3:35:45, which is 3.5958 decimal hours or 215.75 minutes.

Decimal hours are the total seconds divided by 3,600, the form payroll and invoicing systems usually ask for: 7 hours 45 minutes is 7.75 hours. To find the time between a start and an end time of day, use the hours calculator instead.

Durchgerechnete Beispiele

Two additions and a subtraction

Durations, one per line
1:45:30 2:20:15 - 0:30:00
Total
3 h 35 min 45 s
Total as H:MM:SS
3:35:45
Decimal hours
3.5958 h

Prüfquelle: Python fractions: (6330 + 8415 − 1800) s = 12945 s = 3 h 35 min 45 s; 12945/3600 = 3.5958333…

Carrying past 24 hours

Durations, one per line
23:59:59 0:00:01
Total
1 d
Total as H:MM:SS
24:00:00
Decimal hours
24 h

Prüfquelle: 86399 + 1 = 86400 s by hand

A negative total

Durations, one per line
1:00 - 2:30
Total
−1 h 30 min
Total as H:MM:SS
−1:30:00
Decimal hours
-1.5 h

Prüfquelle: 3600 − 9000 = −5400 s by hand

Mixed notations

Durations, one per line
90 min 1.5 h 45 s
Total
3 h 45 s
Total minutes
180.75 min

Prüfquelle: 5400 + 5400 + 45 = 10845 s; 10845 / 60 = 180.75 by hand

Fragen

How do I add hours and minutes together?

Add the hours and the minutes separately, then carry every 60 minutes into an hour. 1:45 plus 2:20 gives 3 hours and 65 minutes, and 65 minutes is 1 hour 5 minutes, so the total is 4:05. Seconds carry into minutes the same way. Typing each duration on its own line here does the carrying for you.

How do I convert minutes to decimal hours?

Divide the minutes by 60. 15 minutes is 0.25 hours, 45 minutes is 0.75 hours, so 7 hours 45 minutes is 7.75 hours, and 3:35:45 is 12,945 ÷ 3,600 = 3.5958 hours. When a timesheet rounds to two decimals, each 0.01 hour is 36 seconds, so 3.5958 is entered as 3.60.

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

Keep the whole hours and multiply the decimal part by 60 to get minutes. 1.5 hours is 1 hour 30 minutes, 3.6 hours is 3 hours 36 minutes and 0.1 hours is 6 minutes. Type an entry such as 3.6 h on a line here to see it shown as 3:36:00.

How do I subtract one time duration from another?

Start the line with a minus sign. If the minutes to take away are larger, borrow 60 minutes from the hours: 2:10 minus 0:45 becomes 1:70 minus 0:45, which is 1:25. The total can go below zero; 1:00 minus 2:30 gives −1:30:00, an hour and a half short.

How do I add times in Excel without the total resetting at 24 hours?

Excel stores a time as a fraction of a day, so a plain h:mm format wraps after 24 hours and 25 hours shows as 1:00. Format the total cell with the custom format [h]:mm:ss and the square brackets let hours run past 24. To get decimal hours in Excel, multiply the time by 24.

Wie genau arbeitet „Time calculator: add and subtract hours and minutes“?

Die Genauigkeit hängt von Ihren Eingaben und den Annahmen der Methode ab. Die Dezimalrechnung nutzt 50 signifikante Stellen, doch Schätzungen, numerische Verfahren und Quelldaten können ungenauer sein. Die angezeigte Rundung beseitigt diese Grenzen nicht. Anhand unabhängiger Quellen geprüfte Rechenbeispiele: 4. Beispielsweise wird „Two additions and a subtraction“ anhand von Python fractions: (6330 + 8415 − 1800) s = 12945 s = 3 h 35 min 45 s; 12945/3600 = 3.5958333… geprüft.

Woher stammt die Methode?

ISO 8601-1:2019 — durations and the extended time format hh:mm:ss; BIPM, The International System of Units (SI), 9th ed. — minute and hour as non-SI units accepted for use with the SI.

Über diesen Rechner

T=∑i±(3600 hi+60 mi+si) s,decimal hours=T/3600T = \sum_i \pm (3600\,h_i + 60\,m_i + s_i)\ \text{s},\qquad \text{decimal hours} = T / 3600

Quellen

  1. ISO 8601-1:2019 — durations and the extended time format hh:mm:ss
  2. BIPM, The International System of Units (SI), 9th ed. — minute and hour as non-SI units accepted for use with the SI

Anhand von Quellen geprüft

Dieser Rechner enthält 4 Rechenbeispiele mit Ergebnissen aus unabhängigen Quellen. Sie laufen in der Testsuite und können auch hier ausgeführt werden.

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