How Far Is the Moon From Earth? Farther Than You'd Guess

How far is the Moon from Earth? On average, 384,400 km (238,855 mi). That sounds like a normal number, but it's farther than your gut tells you. Plot twist: every planet in our solar system fits in the gap between Earth and the Moon, side by side. Jupiter, Saturn, all of them. With a few thousand kilometers to spare. We'll show you how big the gap really is, how long Apollo 11 took to cross it, and why the Moon is a tiny bit farther away every single year.

How far is the Moon from Earth, exactly?

The Moon is on average 384,400 km (238,855 mi) from Earth. That's the figure NASA, Wikipedia, and the Royal Museums Greenwich all use. Light covers that distance in about 1.3 seconds. When the Apollo astronauts radioed Houston, that's exactly the lag you hear in the recordings. Question goes up, 1.3 seconds. Answer comes back, 1.3 seconds.

But 384,400 km is just an average. The Moon doesn't orbit Earth in a perfect circle. It moves on a slight ellipse, which means it's closer some days and farther on others.

Sometimes near, sometimes far: perigee and apogee

When the Moon is closest to Earth, it's called perigee. That's roughly 363,300 km (225,700 mi). The farthest point is apogee, at about 405,500 km (251,966 mi). The difference is over 42,000 km. That's more than the entire circumference of Earth at the equator.

That gap is also why a supermoon looks bigger than a regular full moon. When the full moon happens to land near perigee, it appears about 14 percent larger in the sky. You notice it the moment you compare side-by-side photos.

Do all the planets really fit between Earth and the Moon?

Yes. Add up the diameters of Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, and toss Earth in for fun. The total comes out to roughly 381,000 km. The average Earth-Moon gap is 384,400 km. So all eight planets line up side by side and still leave a few thousand kilometers of breathing room.

Most of that lineup is Jupiter and Saturn. Jupiter alone has a diameter of about 140,000 km. Saturn is around 116,000 km. Together, they eat up almost two thirds of the distance to the Moon. Sounds insane, but the math checks out.

How long does it take to get to the Moon?

Apollo 11 took 75 hours and 49 minutes from launch to lunar landing. That's a little over three days. Most modern moon missions are in the same ballpark, somewhere between three and four days. So if you ever wondered, the answer hasn't changed much in 50 years.

Now the comparison that messes with your head. Drive to the Moon at 60 mph (about 100 km/h) without stopping, and you'd be on the road for 3,844 hours. That's around 160 days straight. Over five months on the freeway with no sleep. Even a commercial jet at 560 mph (about 900 km/h) would need 17 days nonstop.

If you want to test how good your gut is at space distances, try our science estimation questions. Most people are way off when it comes to anything in the solar system.

Why the Moon is farther away every year

The Moon drifts away from Earth at about 3.8 cm per year. That's not a guess. NASA measures it with lasers. Several reflectors have been sitting on the lunar surface since Apollo 11. Researchers fire a laser, the light bounces back, and the round-trip time tells them the distance to within a few millimeters.

The reason for the drift is tides. Earth spins faster than the Moon orbits, and the ocean tides transfer a tiny bit of energy to the Moon. The Moon speeds up slightly, which pushes it outward. Earth's rotation slows down to balance things out. About 1.4 billion years ago, a day on Earth was only around 18 hours. Today it's 24.

3.8 cm per year sounds like nothing. But over long timeframes, it adds up. In 100 million years, the Moon will be roughly 3,800 km farther away than today. We won't notice in our lifetimes. But total solar eclipses, where the Moon perfectly covers the Sun, will eventually stop happening.

How do scientists actually measure the distance?

Today the answer is millimeter-precise, thanks to Lunar Laser Ranging. Three of the reflectors came from Apollo 11, 14, and 15. Two were dropped off by Soviet Lunokhod rovers, and one was added by India's Chandrayaan-3 mission. A laser fires from Earth, the signal returns, and the timing gives the exact distance.

Before lasers, it was harder. Ancient Greek astronomer Hipparchus estimated the distance using lunar eclipses, and he got surprisingly close for someone with no telescope. The technique was clever, the result imperfect, but it kicked off two thousand years of refinement.

Estimation questions where most people miss by a mile

Moon distances are classic Quiztimate territory. The numbers are so big that your gut just stops working. Nobody has an intuitive feel for 384,400 km. That's exactly why these questions are so much fun. They reset your sense of scale.

If you want more in this style, check out our post on how much a cloud weighs. Another number where most people guess way off.

Take-Away

The Moon sits about 384,400 km away on average. Enough room to stack all eight planets in the gap. And every year it drifts a few more centimeters out. If you want more numbers from the solar system that mess with your gut, try our science estimation questions. Free, runs in your browser, perfect for your next road trip.