How to Convert Minutes to Decimal Hours

How to convert minutes to decimal hours

An hour has 60 minutes, so dividing a number of minutes by 60 gives the share of an hour it fills. 45 minutes fills 45 of the 60, and 45 ÷ 60 = 0.75.

1. Split off the whole hours. 135 minutes is 2 hours 15 minutes.
2. Divide the leftover minutes by 60. 15 ÷ 60 = 0.25.
3. Put the whole hours back in front of the point. 2 + 0.25 = 2.25 hours.
4. Round to two decimal places when the division does not end. 2 hours 40 minutes is 2 + 0.666… = 2.67 hours.

A total that is already in minutes takes one division: 200 minutes ÷ 60 = 3.33 hours.

Minutes to decimal hours chart, 1 to 60 minutes

Only multiples of 3 minutes convert exactly, because 3 minutes is 0.05 hours. Every other value repeats forever, such as 20 minutes = 0.333…, so the chart rounds to the nearest hundredth and gives the exact fraction of an hour beside it.

Decimal hours back to hours and minutes

Multiply the decimal part by 60 and round to the nearest minute. 8.4 hours is 8 hours plus 0.4 × 60 = 24 minutes. Rounding matters for two-place values: 0.33 × 60 = 19.8, which rounds to the 20 minutes that 0.33 came from, while cutting off the fraction would give 19.

Decimal part	Minutes	Decimal part	Minutes
0.1	6	0.6	36
0.2	12	0.7	42
0.25	15	0.75	45
0.3	18	0.8	48
0.4	24	0.9	54
0.5	30	1.0	60

Why 7.30 hours is not 7 hours 30 minutes

The digits after the point are hundredths of an hour, not minutes. 0.30 hours is 0.30 × 60 = 18 minutes, so 7.30 hours means 7 hours 18 minutes.

The mix-up costs time in both directions. Typing a 7:30 shift into payroll as 7.30 instead of 7.50 records 12 minutes too little. Reading 7.30 hours on a pay stub as 7 hours 30 minutes expects 12 minutes that were never recorded.

Seconds and decimal places

Seconds divide by 3,600, the number of seconds in an hour. 1 hour 30 minutes 36 seconds is 1 + 30 ÷ 60 + 36 ÷ 3,600 = 1 + 0.5 + 0.01 = 1.51 hours.

At two decimal places, the largest rounding error is 0.005 hours, or 18 seconds, so seconds below that disappear in rounding. Errors that small still add up when rounded daily values are summed. Convert a weekly total once, as the guide to weekly time card totals shows on a five-day week, and let the hours worked calculator do it when there are many days.

Time to decimal in Excel or Google Sheets

Spreadsheets store a time such as 2:15 as a fraction of a 24-hour day (0.09375), so multiplying a time cell by 24 gives decimal hours. The same formulas work in Excel and Google Sheets.

Cell A2 holds	Formula	Result
135 (minutes)	=A2/60	2.25
2:15 (a time)	=A2*24	2.25
2:40 (a time)	=ROUND(A2*24,2)	2.67
8:24 AM (a clock time)	=HOUR(A2)+MINUTE(A2)/60	8.4
2.25 (decimal hours)	=A2/24 with the format [h]:mm	2:15

Without ROUND, 2:40 gives the full value 2.666…, which will not match the two-place figure on a time sheet.

Rounding to tenths of an hour

Some time sheets and billing systems record tenths of an hour, 6 minutes each, instead of hundredths. Under 29 CFR 785.48(b), employers may round recorded start and stop times to the nearest 5 minutes, tenth of an hour or quarter hour. Over a period of time, the rounding must still pay employees for all the time they actually worked.

Minutes past the hour	Nearest tenth	Minutes past the hour	Nearest tenth
0–2	0.0	27–32	0.5
3–8	0.1	33–38	0.6
9–14	0.2	39–44	0.7
15–20	0.3	45–50	0.8
21–26	0.4	51–56	0.9
		57–59	1.0

The table rounds exact halves, such as 3 and 9 minutes, up. Quarter-hour rounding works on the same idea with 15-minute steps, and it is where the 7-minute rule comes from. The subtraction that produces the minutes in the first place is covered in the guide to hours between clock times.

Time Duration Calculator