In the Excel date system, one day is equal to 1, so you can think of time as fractional values of 1, as shown in the table below:
This means if you have a decimal number for minutes, you can divide by 1440 (24 x 60) to get the correct representation of minutes in Excel. After dividing by 1440, you can apply a time format of your choice, or use the result in a math operation with other dates or times.
In the example, since B11 contains 720 (representing 720 minutes) the result is 720/1440 = 0.5. Once a time format like h:mm has been applied, Excel will display 12:00.
To display hours that represent a duration longer than 24 hours, or minutes in durations longer than 60 minutes, you'll need to adjust the number format by adding square brackets.
[h]:mm // hours > 24 [m] // minutes > 60
The brackets signal to Excel that the time is a duration, and not a time of day.