Time to Decimal Calculator

How to use the time to decimal calculator

1. Pick a direction. “Time → decimal” takes hours and minutes and gives decimal hours. “Decimal → time” does the reverse.
2. Type the time the way you have it. The calculator reads 8:45, 8:45:30 (with seconds), 8h 45m, 45 min, 90 minutes and 1h30. A minus sign in front, as in −1:15, is kept, which helps when you are correcting a timesheet.
3. Read the results. The large figure is decimal hours to two places, with the exact value underneath. You also get total minutes, total seconds, the time in h:mm:ss and the value rounded to a tenth of an hour, which some payroll systems use.

The minutes chart under the inputs lists every minute from 1 to 59 with its decimal equivalent, so you can keep it open next to a paper time card.

The formula: divide minutes by 60

An hour has 60 minutes and 3,600 seconds; NIST’s conversion tables list one hour as 3.6 × 10³ seconds and one minute as 60 seconds. Decimal hours simply express the minutes and seconds as a fraction of an hour:

Three examples:

• 8:45 → 8 + 45 ÷ 60 = 8 + 0.75 = 8.75 hours.
• 7:20 → 7 + 20 ÷ 60 = 7.3333…, which rounds to 7.33 hours.
• 1:15:27 → 1 + 15 ÷ 60 + 27 ÷ 3,600 = 1 + 0.25 + 0.0075 = 1.2575 hours.

Going the other way, keep the whole number as hours and multiply the decimal part by 60 to get minutes. For 7.33 hours, 0.33 × 60 = 19.8, which rounds to 20 minutes, so 7.33 hours is about 7:20. For 0.1 hour, 0.1 × 60 = 6 minutes.

Common minute conversions

A handful of conversions cover most time cards. Quarter hours and tenths come out even; most other minutes repeat and get rounded.

Every multiple of 6 minutes is an exact tenth of an hour (6 minutes is 0.1, 12 is 0.2, 18 is 0.3 and so on), and every multiple of 3 minutes is an exact twentieth. Multiples of 3 are the only minute values that convert exactly at two decimal places; the quarter hours are among them.

Why payroll uses decimal hours

Pay is hours times a rate, and you can’t multiply 8:45 by $20 directly. Converting first gives 8.75 × $20 = $175.00. The mistake to avoid is treating the minutes as a decimal: 8:45 is not 8.45 hours. At $20 an hour that slip pays $169.00 instead of $175.00, a $6.00 shortfall on one shift.

The U.S. Department of Labor’s recordkeeping fact sheet says employers must record the hours worked each workday and workweek, and they can use any timekeeping method that is complete and accurate. Many systems store the result in decimal hours to two places, which is why your pay stub might show 38.42 hours instead of 38:25.

Some employers round each punch rather than the total. Federal rules at 29 CFR 785.48 accept recording start and stop times to the nearest 5 minutes, tenth of an hour or quarter hour, as long as it doesn’t, over time, fail to pay people for all the time they actually work. The tenth-of-an-hour figure in the results is there so you can compare with stubs that use 6-minute increments. To total a week of punches with optional rounding and overtime, use the time card calculator.

Rounding: how much does two decimal places cost?

Rounding minutes to two decimal places changes each entry by at most half a hundredth of an hour, which is 18 seconds. At $25 an hour that is at most about 12.5 cents per entry, in either direction. Over a typical week the errors mostly cancel out, but if a system rounds down every time, they add up.

A safer habit is to add the hours and minutes first and convert the total once. Five shifts of 7:20 are 36:40, or 36.67 hours. Converting each shift to 7.33 and adding gives 36.65 hours, about a minute short. Small, but worth knowing when a timesheet doesn’t match a pay stub by a few cents. The hours and minutes calculator adds and subtracts durations before you convert.

For invoices, many freelancers bill in tenths (6-minute blocks) or quarters (15-minute blocks). Converting with this calculator and then rounding to the increment in your contract keeps the numbers transparent for your client.

Other places decimal time shows up

Spreadsheets store time as a fraction of a day, so 6:00 is 0.25 and 18:00 is 0.75. To get decimal hours from a spreadsheet time, multiply by 24: a cell showing 8:45 holds 0.364583…, and 0.364583 × 24 = 8.75. The result in this calculator should match yours once you multiply.

Project trackers, flight logs and lab timesheets often record decimal hours too. A pilot logging 1.3 hours flew 1 hour 18 minutes, and a 0.4-hour task took 24 minutes. Switch to “Decimal → time” to read those entries in hours and minutes.

Example: a full week on a timesheet

Suppose your shifts last week were 7:45, 8:10, 8:00, 7:52 and 6:38. Add the hours and minutes first: the hours come to 36 and the minutes to 45 + 10 + 0 + 52 + 38 = 145, which is 2 hours 25 minutes. The week is 38:25.

Now convert once: 25 ÷ 60 = 0.4167, so the week is 38.42 hours. At $18.50 an hour, that is 38.4167 × $18.50 = $710.71 before taxes and deductions. If your timesheet asks for each day in decimals instead, the five days are 7.75, 8.17, 8.00, 7.87 and 6.63, which add up to 38.42 as well; in this case the rounding happens to cancel out.

When a form asks for decimal hours per day, convert each day separately and keep two decimals, as the form expects. When you only need the week, convert the total. Either way, check that the weekly total in decimals matches the h:mm total you get by adding the minutes. A mismatch of more than a hundredth or two usually means a typo in one of the days.

Sources & assumptions

How this calculator gets its numbers. Full method: our methodology.

• Decimal hours = hours + minutes ÷ 60 + seconds ÷ 3,600.
• Decimal hours back to time: the whole number is hours and the fraction × 60 is minutes, rounded to the nearest minute (or second in the h:mm:ss result).
• The chart rounds minutes ÷ 60 to two decimal places, the precision most payroll forms use.

Sources

1. National Institute of Standards and Technology, NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically. Time conversion factors: 1 hour (h) = 3.6 × 10³ seconds and 1 minute (min) = 6.0 × 10¹ seconds.
2. Electronic Code of Federal Regulations, 29 CFR 785.48, Use of time clocks. Recording start and stop times to the nearest 5 minutes, tenth or quarter of an hour is accepted for enforcement only if, over time, it doesn’t fail to pay employees for all the time they actually work.
3. U.S. Department of Labor, Wage and Hour Division, Fact Sheet #21: Recordkeeping Requirements under the FLSA. Employers must record hours worked each workday and workweek, and may use any timekeeping method (a time clock, a timekeeper, or workers writing down their own times) as long as it is complete and accurate; includes a sample in/out time sheet.

Last reviewed November 2, 2026. Your employer’s payroll system and rounding rule decide the hours that are paid; this converts the numbers you enter.