Size of Mars
Written by Fraser Cain

Mars Compared to Earth. Image credit: NASA/JPL
What is the size of Mars? There are so many ways to measure the size of the Red Planet.
Let's start with diameter. The diameter of Mars is 6,792 km across. Just for comparison, that's only 53% the diameter of Earth. In other words, you could put two planets the size of Mars side by side and they would be a little bigger than Earth.
Next, surface area. The surface area of Mars is 145 million square kilometers. That's only 38% the surface area of the Earth. Just for comparison, that's 28% the surface area of Earth. One interesting fact is that land on Earth covers about 29% of our surface area, with oceans comprising 71%. So the surface area of Mars is the same as the surface area of all the land on Earth.
Now volume. The volume of Mars is 1.63 x 1011 km3. That's only 15% the volume of Earth. You could fit 6 planets the volume of Mars into the Earth and have room to spare.
Finally, let's look at mass. The Mass of Mars is 6.4 x 1023 kg. That translates to 11% the mass of Earth. Because of its lower size and mass, the gravity on Mars is much lower too. You would only experience 38% of Earth gravity standing on the surface of Mars. If you weight 100 kg on Earth, you would only weight 38 kg on Mars.
Want information on other planets? Here's an article about the size of Jupiter, and here's one on the size of Saturn.
Want more information on Mars? Here's a link to NASA's Mars Exploration Program, and here's NASA's World Book on Mars.
We have recorded several podcasts just about Mars. Including Episode 52: Mars and Episode 92: Missions to Mars, Part 1.
Filed under: Astronomy

