What Would I Weigh on Mars?

About Mars Gravity

Mars has a surface gravity of just 3.72 m/s², compared to Earth's 9.81 m/s². That means Mars's gravity is about 38% of Earth's — so you'd weigh roughly a third of what you do at home. The reason comes down to size and mass: Mars has only about 11% of Earth's mass packed into a planet with 53% of Earth's diameter.

For future astronauts, this reduced gravity presents both advantages and challenges. Lifting heavy equipment and building habitats would be far easier than on Earth. But the human body is adapted to 1g, and extended time in lower gravity leads to bone density loss and muscle atrophy. NASA's Human Research Program is actively studying how 0.38g would affect the body over the months or years of a Mars mission.

Interestingly, Mars shares its gravity factor of 0.38 with Mercury, despite the two planets being very different. Mercury is much smaller but denser (it has a huge iron core), while Mars is larger but less dense. The result is nearly identical surface gravity — one of the solar system's fun coincidences.

Fun Mars Facts

• Olympus Mons, the tallest volcano on Mars (and in the entire solar system), rises 21.9 km above the surrounding plains — nearly 2.5 times the height of Mount Everest. Mars's low gravity helped it grow so tall.
• A day on Mars (called a sol) is 24 hours and 37 minutes long — surprisingly close to an Earth day, which is why NASA rover teams can almost keep Earth schedules.
• Mars has two tiny moons, Phobos and Deimos. Phobos is slowly spiraling inward and will either crash into Mars or break apart into a ring in about 50 million years.
• The Valles Marineris canyon system stretches over 4,000 km across Mars — so long it would span the entire continental United States from coast to coast.
• Because of Mars's thin atmosphere (about 1% of Earth's), the sky on Mars appears butterscotch-colored during the day and sunsets look blue — the opposite of Earth.

Frequently Asked Questions

Why is gravity weaker on Mars than on Earth?

Mars has only about 11% of Earth's mass and 53% of Earth's diameter, which together give it a surface gravity of just 3.72 m/s² compared to Earth's 9.81 m/s². That works out to roughly 38% of Earth's gravity. Because gravity depends on both mass and radius, Mars's smaller size and lower mass combine to create a much weaker gravitational pull.

Could humans walk normally on Mars?

Humans could walk on Mars, but it would feel very different from walking on Earth. With only 38% gravity, each step would carry you higher and farther. Studies in reduced-gravity aircraft suggest people naturally shift to a bounding or loping gait — similar to how Apollo astronauts moved on the Moon, but less extreme. Astronauts would also need to readjust after months of zero-gravity travel, which weakens muscles and bones.

How would Mars gravity affect the human body over time?

Living in Mars's 0.38g environment long-term would cause muscle atrophy and bone density loss, though less severely than in zero gravity. NASA estimates astronauts lose about 1-2% of bone mass per month in microgravity; on Mars the rate would be slower but still significant. The cardiovascular system would also adapt, potentially making it difficult to return to Earth's full gravity. This is one of the biggest challenges NASA is researching for future Mars missions.