Time calculator · add, subtract, sum work hours
Add or subtract hours from a time, find how long it is between two times, and total many shifts at once. Also converts 8:30-style times to decimal hours like 8.5 and back.
🔒 What you type is never sent anywhereAdd to or subtract from a time
Between two times
Sum of durations (work hours)
H:MM ↔ decimal hours
Timesheets that use decimal hours (7.75) divide the minutes by 60: 7 h 45 min = 7.75 h, 7 h 30 min = 7.5 h.
Day-based calculations (working days, countdowns) are in the date calculator; length and weight conversions in the unit converter.
Why adding work hours by hand goes wrong
Time is base 60: 8:30 plus 7:45 is 16:15, not 15:75. One or two days are easy, but somewhere in a month of entries a carry gets dropped. In a spreadsheet the cell format has to be [h]:mm before a total over 24 hours displays correctly, and if you do not know that the total simply looks too small. This page converts every line to minutes first — whether it is written as "8:30", "8h 30m", "90m" or "09:00-18:00" — so that mistake cannot happen, and shows the total both as h:mm and as decimal hours so it can go straight into whichever timesheet system you use.
Frequently asked questions
Is what I type sent anywhere?
No. The arithmetic runs in your browser and nothing is transmitted. It works with the internet switched off.
How are overnight shifts handled?
If the end time is earlier than the start, it is taken to be the next day: 22:00 to 06:00 is 8 hours. A line such as "22:00-06:00" in the totals box is read the same way.
How do I take off breaks?
"Time between two times" has its own break field. In the totals box, "Break to subtract per line" is taken off every line written as a start–end range, but not off lines that already give a net duration like "8:30". You can also write "-60m" at the end of a single line to subtract from that line only.
What are decimal hours?
Minutes divided by 60 and added to the hours. 7 h 45 min is 7.75, 7 h 30 min is 7.5, 7 h 20 min is 7.33. Many payroll and timesheet systems use this form, hence the converter.
Which formats does the totals box accept?
One entry per line: "8:30", "8h 30m", "8 hours 15 minutes", "90m", "2.5" (decimal hours) or a range like "09:00-18:00". A day name or date in front of the entry is ignored, so you can paste a week straight from your notes.