Elapsed time calculator, the time between two times, with the working.

Elapsed time is the time that passes between a start and an end. To find it, subtract the start from the end. From 8:15 AM to 3:40 PM, that is 7 hours 25 minutes. This calculator does the subtraction for you, handles an end time that falls past midnight, and shows every step, so you can check it or copy the method into homework.

How to use the calculator

1. On Time between two times, type the Start time and the End time. You can write them as 8:15 am, 815pm, 20:30 or noon. Under each box the page says how it read your entry. Now fills in the time on your clock.
2. For a stretch of a day or more, turn on Use dates and pick the two dates.
3. Read the big result in days, hours, minutes and seconds. The cards give the same time as decimal hours, total minutes, total seconds and days.
4. Open The working to see the steps. Copy result and Copy link keep the answer. Swap start and end turns the two around.
5. To find an end time, press Add or subtract time, type the start, choose Add or Subtract, and type the days, hours, minutes and seconds.

Past midnight

When the end time looks smaller than the start, the time has crossed midnight. Without dates the calculator then counts to the next day. From 10:30 PM to 6:15 AM, the start is 22 hours 30 minutes after midnight, which is 1,350 minutes, and the end is 375 minutes. 375 is less than 1,350, so add one day of 1,440 minutes: 375 + 1,440 − 1,350 = 465 minutes, which is 7 hours 45 minutes. If the two times are the same, the answer is 0. Turn on dates if you mean a full day.

The count-up method for school

Many teachers ask for elapsed time on a number line. The steps are the same every time. Count from the start to the next whole hour, then whole hours, then the rest of the last hour. For 8:15 AM to 3:40 PM: 8:15 to 9:00 is 45 minutes. 9:00 AM to 3:00 PM is 6 hours. 3:00 to 3:40 is 40 minutes. Add the parts: 6 hours and 45 + 40 = 85 minutes, which is 6 hours + 1 hour 25 minutes = 7 hours 25 minutes. The calculator's answer for the same times is also 7 hours 25 minutes. Use it to check your own working.

Worked examples

• 9:05 AM to 11:50 AM. 11:50 is 710 minutes after midnight and 9:05 is 545. 710 − 545 = 165 minutes, which is 2 hours 45 minutes.
• 10:30 PM to 6:15 AM. 7 hours 45 minutes, as worked out above.
• With dates: 3 March 8:00 AM to 5 March 5:30 PM. From 8:00 AM on the 3rd to 8:00 AM on the 5th is 2 days, or 48 hours. From 8:00 AM to 5:30 PM is 9 hours 30 minutes. The total is 57 hours 30 minutes, which is 2 days 9 hours 30 minutes, or 57.5 hours.
• Start plus time: 1:45 PM plus 2 hours 50 minutes. 1:45 PM is 13:45. 13:45 + 2:50 = 16:35, which is 4:35 PM.
• Across midnight: 9:00 PM plus 5 hours 30 minutes. 21:00 + 5:30 = 26:30, which is 2:30 AM, one day later.
• Subtracting: 8:00 AM minus 3 hours 20 minutes. 8:00 − 3:20 = 4:40, so 4:40 AM.

What it does not do

The calculator reads times as they appear on a clock. It does not know about time zones, and it does not apply a daylight saving change. A day is always 24 hours. If a clock change fell between your start and end, the real time that passed can be an hour more or less. For two places, use the time zone converter first. To count pay hours with breaks, use the hours calculator. To count days only, use days between dates. Seconds are counted if you type them, such as 8:15:30 AM. Fractions of a second are not.

Mistakes to avoid

The first is subtracting the clock numbers as if minutes went up to 100. 15.40 minus 8.15 gives 7.25, but the true answer is 7 hours 25 minutes. Turn each time into minutes first, or use the count-up method. The second is leaving off AM and PM, so 3:40 is read as 3:40 in the morning. Add pm, or type 15:40. The third is forgetting the day when the end is on a later date: turn on dates. The fourth is mixing the decimal hours with hours and minutes. 7.25 hours is 7 hours 15 minutes, and 7 hours 25 minutes is 7.4167 hours.

Related pages: Time calculator, Hours calculator, Days between dates and Military time converter.