Add and subtract durations written as hours and minutes, or hours, minutes and seconds. Type something like 1:30 + 2:45 - 0:20 and you get the total in clock form, in decimal hours and in minutes. It's what you need for adding up work hours, journey times or practice sessions.
How to use it
- Type the durations joined by plus and minus signs.
- Read the total.
- Check the decimal hours and total minutes.
- Copy the result.
When it helps
- Adding up hours worked.
- Working out the length of a journey or a film marathon.
- Totalling recording or practice times.
- Subtracting breaks from a shift.
Good to know
- Minutes and seconds must be 59 or less.
- Decimal hours are what payroll and invoicing software expects.
- A negative result is shown with a minus sign.
How durations are added
Each duration is converted to seconds, with a plus or minus sign applied, and the totals are summed. The result is converted back into hours, minutes and seconds. Because it works with durations rather than clock times, there's no wrapping at 24 hours: 20 hours plus 10 hours is 30 hours.
That makes it the right tool for totals, such as weekly hours, rather than for times of day. For adding to a date, use the Add or Subtract Dates tool.
Worked example: weekly hours
Monday 8:15, Tuesday 7:50, Wednesday 8:30, Thursday 6:45, Friday 7:00. Type them joined by plus signs and the total is 38:20, which is 38.33 decimal hours. Subtracting a 0:30 daily unpaid break, five times, gives 35:50.
Payroll systems usually want decimal hours, so 38 hours and 20 minutes becomes 38.33, since 20 minutes is one third of an hour.
Mistakes to avoid
Don't confuse 1:30 as an hour and a half with 1.30, which would be an hour and 18 minutes. Decimal hours and clock notation look similar but aren't the same. The tool shows both so you can see the difference.
Also avoid typing minutes above 59, such as 1:75. If you mean one hour 75 minutes, write 2:15.
Practical uses beyond work
Runners add lap times, musicians total set lists, film fans plan marathons, and travellers add flight and layover durations. Because it handles hours past 24, it also works for long totals such as the length of a series, which can come to several days.
Subtracting is just as useful: take the total running time and subtract what you've already watched to see what's left.
Checking your own sums
Add the hours and the minutes separately, then carry every 60 minutes into an hour. If your manual answer differs from the tool's, look for a minute total above 59 you forgot to carry.
Questions
How do I convert 1:30 to decimal hours?
It's 1.5, and the tool shows this for any total.
Can hours go past 24?
Yes.