Decimal Hours Converter

How the Decimal Hours Converter works

Clocks count in sixties and money counts in hundreds. Payroll and invoicing systems multiply hours by a rate, so they need time written as an ordinary decimal number. A shift of 7 hours 45 minutes is 7.75 hours, not 7.45, and the difference matters: at 20 an hour, reading 7:45 as 7.45 costs the worker 6 in a single day.

How decimal hours work

A decimal hour expresses the minutes as a share of sixty. Divide the minutes by 60 and add the result to the whole hours.

• 7 hours 45 minutes is 7 + 45 ÷ 60 = 7.75.
• 2 hours 20 minutes is 2 + 20 ÷ 60 = 2.333…, usually written 2.33.
• 38 hours 10 minutes is 38 + 10 ÷ 60 = 38.17 to two places.

Going the other way, multiply the fraction by 60. For 6.4 hours, 0.4 × 60 = 24, so 6.4 hours is 6 hours 24 minutes. The converter rounds to the nearest whole minute in that direction.

Reading the result

Converting to decimal gives three readings:

• Decimal hours rounded to two places, which is what most payroll and billing systems store.
• Exact to six places, for when two places is not enough, such as 20 minutes, which is a repeating 0.333….
• Total minutes, handy for systems that log time in minutes.

Seconds are accepted too, as in 1:30:45, and count as a fraction of a minute. Converting from decimal gives the h:mm form, the same thing in words, and the total in minutes and seconds.

Minutes to decimal chart

The chart below the result lists every three minutes from 0 to 57 as decimal hours. Six-minute steps are worth remembering, because each one is exactly a tenth of an hour: 6 minutes is 0.1, 12 is 0.2, 18 is 0.3 and so on. Many law firms and consultancies bill in these six-minute units for exactly that reason.

The quarter hours are the other set worth knowing by heart: 15 minutes is 0.25, 30 is 0.5 and 45 is 0.75.

Rounding and why two places is not always exact

Most minute values do not divide neatly into hundredths. Twenty minutes is 0.3333…, and two places gives 0.33, which is 19.8 minutes. Over one shift the error is a fraction of a minute, but some systems round each entry and then add them up, and others add the exact values and round once at the end. Over a month of daily entries the two methods can differ by a few minutes.

If a payslip seems a little off, convert each day with the exact reading and add them, then compare with the payroll total. A difference of a few hundredths is rounding. A difference of a tenth or more on one day usually means a time was entered as 7.45 instead of 7.75.

Typical uses

• Entering hours into payroll software or a spreadsheet that expects numbers.
• Invoicing hourly work, where the rate is multiplied by decimal hours.
• Reading back a timesheet export that shows 37.5 and wondering what that is on a clock: 37 hours 30 minutes.
• Checking a contractor's bill against their logged time.
• Planning overtime, where a rate of 1.5 times is applied to decimal hours above a threshold.

Spreadsheet tip

In Excel, LibreOffice and Google Sheets, a time such as 7:45 is stored as a fraction of a day, 0.3229. Multiply it by 24 to get decimal hours, and format the cell as a number rather than a time. To go back, divide decimal hours by 24 and format the cell as [h]:mm. The square brackets let totals run past 24 hours instead of wrapping round to zero, which is one of the most common timesheet spreadsheet errors.

Input formats accepted

Hours and minutes can be typed as 7:45, 7:45:30, 7h 45m, 7h or 45m. Minutes and seconds must be 59 or less. Decimal input takes a plain number such as 7.75 or .5.

How many hours each block of minutes is

The formula is decimal hours = minutes ÷ 60. For example, 45 minutes is 45 ÷ 60 = 0.75 hours, so 7 hours 45 minutes is 7.75. Each example below is rounded to two decimal places, which is what most payroll systems store.

Minutes as decimal hours

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