Hour Calculator: Add Hours and Minutes

Convert both times to 24-hour format, subtract the start from the end, then subtract any unpaid breaks. For 8:15 AM to 4:45 PM that is 16:45 - 08:15 = 8 hours 30 minutes. If the end time is earlier than the start time, the shift crosses midnight, so add 24 hours before subtracting. This calculator does all of that for you and shows each step under Explain the math.

Add the minutes first, then the hours, and carry every 60 minutes into an hour. 1 h 45 min + 2 h 30 min is 3 h 75 min, which becomes 4 h 15 min. To subtract, borrow an hour (60 minutes) when the minutes do not cover the difference: 5:10 - 2:30 is 4:70 - 2:30 = 2:40. In the Add / subtract tab you can paste a whole list such as 1:30, 2h15m, 45 min, -0:20 and get the running total.

Work out the full time between clock-in and clock-out, then take off the unpaid break. 9:00 AM to 5:00 PM is 8 hours; with a 30-minute unpaid lunch it is 7.5 hours (7:30). If a break is paid, do not subtract it. The calculator lets you add several breaks and mark each one as paid or unpaid.

If the end time is earlier than the start time, it assumes the shift ended the next day and adds 24 hours, and a badge reads "ends next day". 10:00 PM to 6:00 AM is 8 hours. For shifts longer than 24 hours, use Extra full days. If the shift spans a daylight saving change, use the Between two dates tab, which uses the real clock change for your time zone.

9 to 5 is 8 hours, or 7.5 hours if you take an unpaid 30-minute lunch and 7 hours with an unpaid hour. 8am to 5pm is 9 hours (8.5 with a 30-minute lunch). 7am to 3pm is 8 hours (7.5 with lunch). The table above lists these and a few more, and each row loads straight into the calculator.

From 0100 to 1259 the hour stays the same (0930 is 9:30 AM, 1230 is 12:30 PM). From 1300 to 2359 subtract 12 and add PM (1745 is 5:45 PM). 0000 is 12:00 AM (midnight) and 1200 is 12:00 PM (noon). Use the converter on this page for the exact result, or the 0000 to 2359 chart.

Use the Between two dates tab. Enter a start and end date and time, and pick a time zone for each if they differ. The result is shown as days, hours and minutes, plus decimal hours and total minutes. Because each moment is converted to a real UTC instant first, daylight saving changes are handled: the night the clocks go forward is one hour shorter, the night they go back is one hour longer.

Hours and minutes (H:MM) split a duration into 60-minute units, so 7:45 is seven hours and 45 minutes. Decimal hours express the same duration as a fraction of an hour: 45 minutes is 0.75, so 7:45 is 7.75 hours. Payroll systems usually want decimals (multiply by the hourly rate), while people read H:MM. The calculator shows both, plus total minutes, for every result.

With the start time in A1 and the end time in B1, =MOD(B1-A1,1)*24 gives decimal hours and handles overnight shifts, and =MOD(B1-A1,1) formatted as h:mm gives hours and minutes. Subtract a break in minutes in C1 with =(MOD(B1-A1,1)-C1/1440)*24. To add many durations, use =SUM(A1:A10) and format the cell as [h]:mm so totals above 24 hours do not wrap. Copy-ready formulas are on this page.