Time usually appears as hours, minutes and seconds on clocks, watches, websites and computers. You use it to plan your day, schedule appointments and receive hourly compensation. However, some calculations involving time, such as within spreadsheets or computer programs, become easier when they are expressed as decimal numbers. Such numbers are not useful for ordinary viewing but can easily be converted to regular time.
When a time is expressed as a decimal that includes hours, the hours remain the same upon conversion. Multiply the remaining decimal by 60 to determine the minutes. If that equation produces a decimal number, multiply the decimal by 60 to produce the seconds. For example, with a decimal number such as 9.47, do the following:
Subtract 9 for use as the hours. Multiply .47 by 60 to equal 28.2 minutes. Multiply .2 by 60 to equal 12 seconds.
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Thus, 9.47 equals 8 hours, 28 minutes and 12 seconds.
When a time is expressed as a decimal that includes only minutes, divide by 60 to express it as an hour decimal, then calculate hours and minutes as described in the previous step. For example, dividing 135.5 minutes by 60 produces an hour decimal of 2.25833. Calculating this number according to step 1 produces 2 hours, 15 minutes and 29.988 seconds, which can be rounded to 30.
Browse an online calculator such AnalyzeMath.com. Type the hour decimal into the “Decimal Time” box and click “Enter.” The site displays the hours, minutes and seconds.