Voltti
Free tool

Time duration calculator
for any two times.

Find the hours and minutes between two times, even past midnight, or between two dates. Get the answer in hours and minutes, decimal hours and total minutes, with no signup.

Duration0h 00mHours and minutes
Decimal hours0.00Minutes ÷ 60
Total minutes00 seconds
Crosses midnightNoSame day
Stop guessing

Your computer already knows your hours.

Working out start and end times by hand is fine once in a while. If you work on a computer, Voltti counts every real minute for you, in every app and work website, and stops counting when you step away. No timer to start or stop.

Download for Mac Download for Windows

Free · macOS 13 or later · Windows 10 and 11

How it works

How to calculate time duration.

  1. Write both times in 24-hour form. 8:45 AM is 8:45 and 5:20 PM is 17:20.
  2. Subtract the start from the end. If the minutes come out negative, borrow 60 minutes from the hours.
  3. If the end is earlier than the start, add 24 hours. That means the time ran past midnight.
  4. Take out any break. Subtract the break minutes from the result.
  5. Convert to decimal if you need it. Divide the minutes by 60 and add them to the hours.

Worked example

From 8:45 AM to 5:20 PM with a 30 minute lunch:

  1. 17:20 minus 8:45. The minutes give 20 minus 45, which is negative, so borrow an hour: 80 minus 45 is 35 minutes, and 16 minus 8 is 8 hours. That is 8h 35m.
  2. Take out the 30 minute break: 8h 05m.
  3. In decimal: 5 ÷ 60 is 0.08, so 8.08 hours. In minutes: 8 × 60 + 5 is 485 minutes.

An overnight time works the same way. 10:00 PM to 6:00 AM is 6:00 minus 22:00, which is minus 16 hours. Add 24 and you get 8 hours.

Across dates, count the full days first. Monday 9:00 AM to Wednesday 1:30 PM is 2 days, then 4 hours 30 minutes more: 2 days 4h 30m, or 52.5 hours.

FAQ

Time duration, answered.

How do I find the hours between two times?

Subtract the start time from the end time. If the end is earlier than the start, add 24 hours, because the time ran past midnight. Enter both times above and the calculator does it for you.

How many hours is 10 PM to 6 AM?

8 hours. The end time is earlier than the start, so the calculator counts it as running past midnight into the next day.

How do I turn hours and minutes into decimal hours?

Divide the minutes by 60 and add them to the hours. 3 hours 45 minutes is 3 + 45 ÷ 60 = 3.75 hours. The calculator shows both.

Can it count the time between two dates?

Yes. Pick Between two dates, then enter a start date and time and an end date and time. You get the total in days, hours and minutes, plus total hours and minutes.

Does it account for daylight saving time?

No. Every day counts as 24 hours, so a clock change inside your range does not add or remove an hour. If your range crosses a clock change, adjust by one hour yourself.

What if the start and end time are the same?

In Between two times, the same start and end gives 0 hours. To measure a full 24 hours or more, use Between two dates.

Is my data saved anywhere?

Your times stay in your browser so they're still there when you come back. Nothing is sent to a server.

Is there a way to track my time automatically?

If you work on a computer, yes. Voltti for Mac and Voltti for Windows record every real minute in your apps and work websites, with no timer to start or stop. The free plan includes automatic tracking. For a full week of shifts, try the work hours calculator.