Hours to Decimal Calculator

DateMath divides the minutes by 60 and the seconds by 3,600 and adds them to the hours, then rounds to two decimal places, the hundredths of an hour most timesheets use, and shows the exact value when rounding changed it. Going back, DateMath multiplies the decimal part by 60 for the minutes and rounds to the nearest second, so 7.3 hours is exactly 7 hours 18 minutes.

• US hours-worked rules. DateMath counts exact minutes and subtracts only the breaks you enter. The federal Fair Labor Standards Act rules count rest breaks of about 5 to 20 minutes as work time but not bona fide meal periods (ordinarily 30 minutes or more), and allow rounding clock times to the nearest 5 minutes, tenth or quarter of an hour only if employees are still paid for all the time they work. Source: 29 CFR 785.18, 29 CFR 785.19, 29 CFR 785.48.

DateMath's date math is tested against more than 100 cases worked out by hand. Every worked example and table on the site is computed with the same code the calculators run, so a page and its calculator can't disagree.

Decimal hours write a length of time as one number: 7 hours 45 minutes is 7.75 hours. Timesheets, payroll systems and invoices use them because an hourly rate can only be multiplied by a decimal. This converter turns hours and minutes into decimal hours, and decimal hours back into hours, minutes and seconds.

Hours and minutes to decimal

Enter whole hours, minutes and seconds. Minutes and seconds above 59 are fine: they roll over, so 90 minutes converts to 1.50 hours. The result is rounded to two decimal places, and when the exact value has more digits it is shown too, so you know what the rounding did.

Decimal to hours and minutes

Enter decimal hours, such as 8.65, and read the hours, minutes and seconds, the hours:minutes form and the totals in minutes and seconds. The result is rounded to the nearest second.

Every minute of an hour as a decimal of an hour. Values that don't end after two places show four in brackets. Add the decimal to the whole hours: 8 hours 36 minutes is 8.60.

Divide the minutes by 60 and the seconds by 3,600, then add both to the whole hours. Example: 2 hours, 14 minutes, 24 seconds.

1. Minutes: 14 ÷ 60 = 0.2333.
2. Seconds: 24 ÷ 3,600 = 0.0067.
3. Add them to the hours: 2 + 0.2333 + 0.0067 = 2.24 hours.

A quick check: the decimal part of an hour is always less than 1, and 30 minutes is exactly 0.5. A decimal part above 0.5 means more than half an hour.

Keep the whole hours and multiply the decimal part by 60 to get the minutes. Example: 8.65 hours is 8 hours, and 0.65 × 60 = 39 minutes, so 8 hours, 39 minutes.

When the minutes come out with a decimal part, multiply that part by 60 for the seconds: 3.1416 hours is 3 hours, 0.1416 × 60 = 8.496 minutes, and 0.496 × 60 = 29.76 seconds. Rounded to the nearest second, that is 3 hours, 8 minutes, 30 seconds.

A decimal point is not a colon. In decimal hours the digits after the point are hundredths of an hour, not minutes, so reading them as minutes gives the wrong time:

Before you add up or pay a list of hours, check which form each one is in. A timesheet column with values such as 7:45 is hours:minutes; one with 7.75 is decimal hours.

Some payroll and billing systems record time in tenths of an hour. A tenth is 6 minutes, so each 0.1 adds 6 minutes:

A work hours decimal calculator matters most when hours are paid. Gross pay is decimal hours × the hourly rate, and the rounding step decides the cents. 7 hours, 20 minutes is 7.3333 hours, so at $15.00 an hour it pays exactly $110.00. Rounded to 7.33 hours first, it pays $109.95.

• Add first, round once. Total the exact minutes of a pay period, then convert to decimal hours. The time card calculator totals a week or two this way, with the decimal hours and the gross pay.
• Know your employer's rounding. Clock times rounded to the nearest 5 minutes, tenth or quarter hour are allowed under federal rules only when they average out, so that employees are paid for all the time they work (29 CFR 785.48). DateMath itself never rounds the time, only the displayed decimal.
• Hours from a clock-in and clock-out. To get the hours and minutes of a shift first, use the hours calculator; it shows the decimal hours as well.

Spreadsheets store a time as a fraction of a day, so 12:00 is 0.5. Multiply by 24 to get decimal hours, and divide by 24 to go back:

• Time to decimal hours: with 7:45 in A1, =A1*24 returns 7.75. Format the result cell as a number, not as a time.
• Decimal hours to time: with 7.75 in B1, =B1/24 returns 7:45 when the cell is formatted as [h]:mm. The square brackets let totals run past 24 hours.
• From separate hours and minutes: =A2+B2/60 with the hours in A2 and the minutes in B2.

Google Sheets uses the same formulas and the same [h]:mm number format.

• A quarter hour is 0.25, half an hour 0.50 and three quarters 0.75.
• A 40-hour week is 40.00 decimal hours; 37 hours 30 minutes is 37.50.
• 1 hour, 40 minutes is 1.67 (1.6667) hours, and 1,000 minutes is 16.67 (16.6667) hours.
• One minute is 0.02 (0.0167) hours and one second 0.000278 hours.

For the time between two clock times, use the hours calculator; to add hours and minutes to a date and time, the time calculator.