Walking to the Moon

The Moon is the standard reference for an absurd distance, and it turns out to be a genuinely instructive one, because it is the first of these thought experiments that a human lifetime cannot cover.

The distance

The average distance from Earth to the Moon is 384,400 kilometres, or 238,855 miles. It is not constant: the Moon's orbit is elliptical, so the distance ranges from about 356,500 kilometres at perigee to about 406,700 at apogee — a swing of over 50,000 kilometres, which is more than the circumference of the Earth.

The Moon is also receding. Laser ranging using retroreflectors left on the surface by the Apollo missions has measured the drift at about 3.8 centimetres per year, caused by tidal interaction with the Earth. Over a fifty-year walk, the Moon would move about 1.9 metres further away — roughly two and a half extra steps, which is the only genuinely negligible number on this page.

The step count

At an average adult stride of 0.75 metres, 384,400 kilometres is about 512.5 million steps.

Target	Distance	Steps
Around the Earth	40,075 km	53.4 million
To the Moon	384,400 km	512.5 million
To the Moon and back	768,800 km	1.03 billion
To the Sun	149.6 million km	199.5 billion

The Moon is about 9.6 times the circumference of the Earth. That relationship is the useful one to carry: walking to the Moon is walking around the world roughly ten times.

How long it would take

At 10,000 steps a day, 512.5 million steps takes 140 years. At 20,000 a day, 70 years. At 30,000 a day — roughly 15 miles, a serious daily effort sustained without a single rest day — it is 47 years.

This is where the exercise stops being playful. A person walking 10,000 steps a day from birth to age 90 accumulates about 328 million steps, which is 64 per cent of the way. Nobody walks 10,000 steps a day from birth. A realistic lifetime total for an active person is somewhere between 150 and 250 million steps, which puts the Moon comfortably out of range and the Earth's circumference comfortably within it, several times over.

How Apollo compares

Apollo 11 covered the distance in about 76 hours. Its crew then walked, on the surface, roughly 250 metres in total — around 330 steps — during a single extravehicular activity of about two and a half hours.

Later missions did far more. Apollo 17's crew, with the lunar rover, drove about 36 kilometres across three excursions. Cumulatively, the twelve people who have walked on the Moon covered a distance on foot that any commuter would consider unremarkable.

Lunar gravity is about one sixth of Earth's, which changes gait fundamentally. Astronauts found normal walking inefficient and adopted a loping, two-footed hop, because at that gravity the pendulum mechanics that make human walking efficient break down at very low speeds. If you could somehow walk the whole way, the last few thousand kilometres would require a different gait entirely.

Distances you can actually reach

• A million steps is about 750 kilometres — London to the Scottish Highlands, or New York to Chicago. Reachable in about 100 days at 10,000 a day.
• Ten million steps is about 7,500 kilometres, roughly the distance from New York to Rome and back. About 2.7 years.
• A hundred million steps is 75,000 kilometres, nearly twice around the world. About 27 years.

The Moon stays out of reach. Everything else on the list is achievable by an ordinary person doing an ordinary amount of walking, which is the more encouraging half of the arithmetic.

Your step count, by height

Step length varies with height by more than 25 per cent across the adult range, so the single figure at the top of this page will not be right for everyone. Here is the same distance for a range of heights, using the standard estimate of 0.414 × height.

Your height	Est. step length	Steps for this route
1.55 m	0.64 m	598,753,678
1.65 m	0.68 m	562,810,924
1.75 m	0.72 m	530,206,705
1.85 m	0.77 m	501,827,495
1.95 m	0.81 m	476,331,922

These are estimates. If you want a figure that matches your own gait, our guide to measuring your stride length takes about five minutes.

Common questions

How many steps would it take to walk to the Moon?

About 512.5 million, based on an average distance of 384,400 kilometres and a 0.75-metre adult stride.

How long would it take?

About 140 years at 10,000 steps a day, or 70 years at 20,000 — longer than a human lifetime of continuous walking.

How far did astronauts actually walk on the Moon?

Very little. The Apollo 11 crew covered roughly 250 metres on foot. Later missions ranged much further, but used the lunar rover to do it.

Try your own route

Enter any two places into the step calculator to get a figure for a walk of your own, or browse all twenty routes and eight articles.