An hour has 60 minutes, so any fraction of an hour is converted by multiplying it by 60. This page solves the conversion; if you wonder why the hour is divided into 60 parts and not 100, the article why an hour has 60 minutes explains it. Choose “Hours to minutes” or “Minutes to hours” in the converter and enter the duration as an integer, fraction, decimal or mixed number.
Worked example: 1/8 of an hour in minutes
A break lasts 1/8 of an hour. How many minutes and seconds is that?
- Multiply by 60. (1/8) × 60 = 60/8.
- Simplify. 60/8 = 15/2, which is 7.5 minutes.
- Split off the decimal part. 0.5 minutes is 30 seconds.
Result: 7 minutes and 30 seconds.
Check: eight equal breaks add up to 8 × 7.5 = 60 minutes, the full hour.
Most common fractions of an hour
The table lists the fractions people look up most. All of them give a whole number of minutes, because 60 has many divisors, which is why they show up in schedules, recipes and timesheets. If your fraction is not listed, multiply it by 60 as in the example.
| Fraction of an hour | Minutes |
|---|---|
| 1/2 h | 30 min |
| 1/3 h | 20 min |
| 1/4 h | 15 min |
| 1/5 h | 12 min |
| 1/6 h | 10 min |
| 1/10 h | 6 min |
| 1/12 h | 5 min |
| 1/15 h | 4 min |
| 1/20 h | 3 min |
| 1/60 h | 1 min |
The other fractions come from adding these: 2/3 h is two times 20 minutes, that is, 40 min, and 5/6 h is 50 min.
How to convert minutes to a fraction of an hour
Put the minutes over 60 and simplify. For 15 minutes, 15/60 reduces by dividing by 15 and gives 1/4 of an hour. For 12 minutes, 12/60 reduces by dividing by 12 and gives 1/5 of an hour. With 40 minutes, the common divisor is 20 and you get 2/3 of an hour.
When the result does not reduce to a small denominator, the fraction is still exact. For example, 25 minutes gives 25/60 = 5/12 of an hour, and its decimal has a repeating part. To see that decimal with all its digits, use fraction to decimal.
Why 1.30 hours is not 1 hour and 30 minutes
On a timesheet, the decimal point separates whole hours from a fraction of an hour. So 1.30 h means one hour plus 0.30 h, not one hour plus 30 minutes.
Clock format is a different thing: 1:30 is 90 minutes and 1.30 h is 78 minutes. The converter works with numbers, so it does not accept “1:30” as input and does not apply clock-punch rounding or daylight saving changes.
Where this conversion helps
Speed problems ask for time in hours: 45 minutes enters as 3/4 of an hour, and the guide to speed, distance and time with fractions solves them with examples. If you need a part of another quantity, such as 3/4 of 80 minutes, use fraction of a number. When time is proportional to something else, for example pages read per minute, set up a rule of three. For more everyday uses, from recipes to measurements, see the guide to fractions in everyday life.
Frequently asked questions
What fraction of an hour is 20 minutes, and how do you write it as a decimal?
It is 1/3 of an hour, because 20/60 simplifies by dividing by 20. As a decimal it is 0.333…, written 0.3̅. If a form asks for two decimal places, 0.33 h equals 19.8 minutes, that is, 19 min 48 s: twelve seconds short of the real 20 minutes on every entry.
How do I convert 7 hours 20 minutes to decimal hours?
Convert everything to minutes and divide by 60: 7 × 60 + 20 = 440 min, and 440/60 = 22/3 h. As a decimal that is 7.3̅ h. Rounded to 7.33 h, it equals 439.8 minutes. If you need a single value, record 22/3 or say how many decimal places you used.
How many seconds is 3/8 of an hour?
Multiply by 3600, which is 60 × 60: (3/8) × 3600 = 1350 seconds. That is 22.5 minutes, or 22 min 30 s. The h:m:s view of the result splits the same duration into hours, minutes and seconds.
Why is 1.5 h equal to 1 h 30 min and not 1 h 50 min?
Because 1.5 h is one hour plus 0.5 h, and half an hour is 30 minutes. The 50 would be right only if an hour had 100 minutes. A duration of 1 h 50 min is 110 minutes, that is, 11/6 h, which as a decimal is 1.83̅ h.