At Mars' orbital speed of 24 km per second, it takes the planet 24 hours and 37 minutes to complete one rotation. That is just a little more than a day on Earth.
The Earth zips around the Sun at about 67,000 miles per hour, making a full revolution in about 365 days – one year on Earth. Mars is a little slower, and farther from the sun, so a full circuit takes 687 Earth days – or one Mars year.
