7.35 × 10¹⁹ t1.62 × 10²³ lb
The Moon has a mass of about 7.35 × 10²² kg (roughly 1.62 × 10²³ lb), or 73.5 quintillion tonnes. NASA gives 7.346 × 10²² kg, about 1.2% of Earth’s mass. Out in space it has no weight in the everyday sense, so this is its mass: how much matter it is made of.
Weight is the push of something on whatever holds it up, and nothing holds the Moon up. It is in free fall around the Earth, moving sideways fast enough to keep missing it, just like the space station. So astronomers talk about its mass: NASA’s Moon fact sheet gives 7.346 × 10²² kg, which the game rounds to 7.35 × 10²² kg.
There is still a force between the two. Using NASA’s figures for Earth’s gravity and the Moon’s average distance of 384,400 km, Earth pulls on the Moon with about 2 × 10²⁰ newtons, and the Moon pulls back on Earth just as hard. That is what 20 quadrillion tonnes would weigh sitting on the ground here.
You watch what its gravity does to other things. The Earth and Moon both circle a shared balance point, about 4,670 km from Earth’s centre, still inside the planet. That makes Earth wobble once a month, which shows up as small shifts in where the Sun and planets appear in the sky. Divide 4,670 km by the remaining 379,730 km to the Moon and you get a Moon 1/81.3 the mass of Earth. Isaac Newton tried it from the tides instead and got about 1/40, twice too heavy.
Spacecraft orbiting the Moon, plus decades of laser pulses bounced off reflectors left by Apollo astronauts, pin down how strongly it pulls. NASA’s Jet Propulsion Laboratory gives that pull (its mass times the gravitational constant, G) to ten digits: 4,902.800118 km³/s². The weak link is G itself, known only to about 1 part in 44,000, so the Moon’s mass in kilograms is good to about four or five digits.
In 2012, NASA’s twin GRAIL probes, Ebb and Flow, flew one behind the other and measured the tiny changes in the distance between them as they passed over mountains, craters and buried lumps of dense rock. The result was the most detailed gravity map of the Moon so far, showing how its mass is spread out. One surprise: the crust is only 34 to 43 km thick on average, 10 to 20 km thinner than expected.
The Moon takes up about 2% of Earth’s volume but has only 1.23% of its mass. Its average density is 3.34 g/cm³, against 5.51 for Earth, because it is mostly rock with far less iron. Laser ranging has still found strong evidence of a small liquid core.
Less mass and a smaller size give it a surface gravity of 1.62 m/s², 0.165 of Earth’s, or about one sixth. Your mass stays the same, but someone who weighs 150 lb (68 kg) at home would weigh about 25 lb on the Moon, and a bathroom scale would read about 11 kg.
About 1.62 × 10²³ lb (162 sextillion pounds). That is about 73.5 quintillion metric tonnes, or roughly 81 quintillion US tons.
About 81 by mass, since Earth is 81.3 times heavier. By volume you would need about 49, because the Moon is less dense than Earth.
About one sixth of what you weigh on Earth (16.5%). A 200 lb person would weigh about 33 lb there, although their mass would not change at all.
Less than 390 kg in total. The six Apollo landings brought back 382 kg (842 lb) of rock and soil, the Soviet Luna probes 301 g, and China’s Chang’e 5 and Chang’e 6 about 1.7 kg and 1.9 kg, the latter from the far side.
Yes, by about 3.8 cm (1.5 in) a year. Lunar laser ranging measures the Earth to Moon distance to within about 3 cm, so the drift shows up clearly over the decades. It comes from tides, and it does not change the Moon’s mass.
Last checked October 2, 2026.
