Calculate gravitational acceleration (g) on any celestial body by entering its mass and radius. You can also select from preset bodies like Earth, Mars, Moon, Jupiter, and more. The calculator applies the formula g = GM/R² and returns the acceleration due to gravity in m/s², along with a comparison to Earth's surface gravity.
Acceleration Due to Gravity (g)
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Relative to Earth's g
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Gravity in ft/s²
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Effective Radius Used
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The acceleration due to gravity (g) is the acceleration experienced by a freely falling object under the influence of gravity alone. On Earth's surface, g ≈ 9.81 m/s². It is a vector quantity directed toward the center of the celestial body and is measured in meters per second squared (m/s²).
The formula is g = GM/R², where G is the Universal Gravitational Constant (6.674 × 10⁻¹¹ m³ kg⁻¹ s⁻²), M is the mass of the celestial body in kilograms, and R is the radius (or distance from the center) in meters. The result gives the gravitational acceleration at that distance.
The Universal Gravitational Constant (G) has a value of 6.674 × 10⁻¹¹ m³ kg⁻¹ s⁻². It appears in Newton's law of universal gravitation and is a fundamental physical constant used to calculate gravitational forces and accelerations across all celestial bodies.
To find g on Mars, use its mass (6.39 × 10²³ kg) and mean radius (3,389,500 m) in the formula g = GM/R². This gives approximately 3.72 m/s², which is about 38% of Earth's surface gravity. You can select Mars from the preset dropdown in this calculator to auto-fill these values.
The Moon has a mass of 7.342 × 10²² kg and a mean radius of 1,737,400 m. Plugging these into g = GM/R² gives approximately 1.62 m/s², which is roughly 1/6th of Earth's gravity. Select Moon from the preset list to calculate this automatically.
Yes. As you move away from the surface, the distance R in the formula increases (R = radius + altitude), causing g to decrease. For example, at the International Space Station (~400 km above Earth), g is about 8.69 m/s², not zero — astronauts appear weightless due to orbital free-fall, not absence of gravity.
Yes. By selecting 'Custom' and entering the mass and radius of any celestial body — including exoplanets, dwarf planets, or asteroids — you can calculate the gravitational acceleration at its surface or at a given altitude above it.
Mass is entered in kilograms (kg), radius and altitude in meters (m), and the output gravitational acceleration is given in m/s² (SI unit) as well as ft/s² for reference. The result is also expressed as a multiple of Earth's standard gravity (9.80665 m/s²) for easy comparison.