Finding how many minutes are in a day is a common and useful time conversion. The usual method involves dividing the day into hour and then hours into minutes. Here is how you find minutes in a day, for both the solar day and sidereal day.
- There are 1440 minutes in a 24-hour day or solar day.
- There are 1436 minutes in a sidereal day.
Solar Day vs Sidereal Day
While we often use the term “day” to describe the time it takes for the Earth to complete one rotation, it’s important to note that there are actually two types of days: a solar day and a sidereal day.
A solar day is the time it takes for the Earth to rotate once on its axis relative to the Sun. It is the basis for our 24-hour day. Theoretically, it is the time from sunrise to sunrise, but the lengths of days and nights vary. In contrast, a sidereal day is the time it takes for the Earth to complete one rotation relative to the distant stars. Due to Earth’s orbit around the Sun, a sidereal day is slightly shorter than a solar day, lasting approximately 23 hours, 56 minutes, and 4.1 seconds.
How to Calculate How Many Minutes in a Day
The time conversion is easy as long as you set it up correctly so the unwanted units cancel out. First, convert days to hours and then hours to minutes.
1 day = 24 hours
1 hour = 60 minutes
Now, multiply the number of hours in a day by the number of minutes in an hour and get the number of minutes in a day.
For a solar (24 hour) day:
24 hours/day × 60 minutes/hour = 1,440 minutes/day
Notice that the hours cancel out, leaving you with minutes per day.
For a sidereal day, the easy method is just subtracting 4 minutes from the solar day:
1440 minutes – 4 minutes = 1436 minutes
Otherwise, set up the unit conversion exactly the same way. The key difference is that you start with a 23 hour day and add the extra minutes (which don’t require conversion):
(23 hours/day x 60 minutes/hour) + 56 minutes = 1380 + 56 = 1436 minutes/day
Difficulties and Importance
The main difficulty people having in doing time conversions is dividing instead of multiplying. Check your work by making certain the answer makes sense. If you set the math up incorrectly, you’ll get a very small decimal number. But, that does not make sense because you know there are a lot of minutes in a day!
Knowing how to find how many minutes there are in a day is important for two reasons. First, it helps with time management, since some tasks require minutes rather than hours. Second, it provides a better understanding of the relationship between the Earth’s rotation and our measurement of time.
References
- Allen, Clabon Walter; Cox, Arthur N. (2000). Allen’s Astrophysical Quantities. Springer. ISBN 0-387-98746-0.
- McCarthy, Dennis D.; Hackman, Christine; Nelson, Robert A. (2008). “The Physical Basis of the Leap Second”. The Astronomical Journal. 136 (5): 1906–1908. doi:10.1088/0004-6256/136/5/1906