Time Converter

Converting time without tripping over base 60

Time units are exact and simple: 60 seconds in a minute, 60 minutes in an hour, 24 hours in a day, which makes 3,600 seconds in an hour and 86,400 in a day. What makes time awkward is that we write it in base 60 and calculate in base 10.

The classic mistake is reading a decimal as clock time. 1.5 hours is one and a half hours, 1 h 30 min, not 1 h 50 min. And 2 h 45 min is 2.75 hours, not 2.45. The converter above gives both forms for every result: the decimal figure you need for a spreadsheet or a payroll system, and the hours-and-minutes figure you would read off a clock.

To do it by hand, split the number. Keep the whole hours, then multiply the decimal part by 60 to get minutes: 7.6 hours is 7 hours and 0.6 × 60 = 36 minutes. In the other direction divide the minutes by 60: 7 h 36 min is 7 + 36 ÷ 60 = 7.6 hours.

Besides the unit converters, this section has tools for the jobs where time arithmetic usually goes wrong:

• Decimal to time: decimal hours to hours, minutes and seconds, and back.
• Time clock calculator: hours worked between clock-in and clock-out, minus a break.
• Work hours calculator: add up the shifts of a week.
• 24-hour to 12-hour: 18:45 to 6:45 PM and back.

Counting days between dates is a calendar question rather than a unit conversion; our sister site Time To Celebrate covers it.