How is a day measured on other planets?

The easiest way to measure a full day on other planets is to look at the amount of time it takes for the planet to make one full rotation.
Here’s a list of how long a day is on all the planets in our solar system:

  • Mercury – 1,408 hours
  • Venus – 5,832 hours
  • Earth –  24 hours
  • Mars – 25 hours
  • Jupiter – 10 hours
  • Saturn – 11 hours
  • Uranus – 17 hours
  • Neptune – 16 hours