Fold ten: around ten centimeters.

Fold twenty: more than 100 meters.

Fold thirty: more than 100,000 kilometers.

The process hasn't changed.

The rule hasn't changed.

The paper simply keeps doubling.

But doubling becomes extraordinary when repeated enough times.

Forty folds—and the numbers become absurd

At 40 folds:

0.1 mm × 2⁴⁰ ≈ 109,951,162 kilometers

That's about 110 million kilometers.

This is an enormous distance.

For comparison, NASA places the average Earth-Sun distance at about 150 million kilometers. (NASA Science)

So a hypothetical 40-fold stack would already be approaching the scale of the distance between Earth and the Sun.

Then comes fold 41.

Double it again:

≈ 220 million kilometers

And fold 42:

≈ 440 million kilometers

Now something remarkable happens.

That hypothetical thickness has surpassed the average Earth-Moon distance by a significant margin.

Scientific American recently revisited this famous calculation and arrived at the same result: using a starting thickness of approximately 0.1 millimeter, 42 folds are enough mathematically to exceed the average distance to the Moon. (Scientific American)

NASA independently confirms that the Moon's average orbital distance is about 384,400 kilometers. (NASA Space Place)

So the famous claim isn't simply an internet exaggeration.

Under the idealized mathematical assumptions, 42 doublings really are enough.

And that is perhaps the most surprising part.

You don't need hundreds or thousands of folds.

You don't even need 100.

You need only 42.

But could you actually fold paper 42 times?

No.

And this is an extremely important distinction.

The calculation is mathematically correct, but the physical process is not realistically achievable with an ordinary sheet of paper.

The problem is that folding paper isn't an abstract mathematical operation.

Paper has physical properties.

It has thickness.

It has stiffness.

It has a limited surface area.

It resists bending.

And every time you fold it, the stack becomes thicker while the remaining surface area available for another fold becomes smaller.

After enough folds, the forces required to continue become enormous.

The paper also becomes increasingly difficult to manipulate because each fold creates a thicker and more rigid stack.

This is why the famous paper-folding thought experiment should be understood as a demonstration of mathematics, not as a practical engineering recipe.

There is, however, a fascinating real-world connection.

NASA's James Webb Space Telescope relies on extremely sophisticated folding and deployment techniques to fit a huge structure into a rocket and then unfold it in space. NASA describes Webb's primary mirror as consisting of 18 segments, while other major structures, including its enormous sunshield, also had to be folded for launch and deployed after reaching space. (NASA Science)

The engineering behind Webb demonstrates that folding large structures is possible.

But it also demonstrates why real-world folding is far more complicated than simply multiplying a number by two.

The hidden problem: the paper is shrinking at the same time

There is another detail that makes the thought experiment even stranger.

Every time you fold the paper in half, you don't just double its thickness.

You also reduce its dimensions.

After one fold, one dimension is roughly half its original size.

After two folds, depending on how you fold it, the available dimensions become smaller still.

After dozens of folds, the hypothetical remaining sheet would become incredibly tiny.

Scientific American points out that after 42 folds, the mathematical object would no longer resemble a useful sheet of paper at all; its remaining dimensions would have become microscopic. (Scientific American)

So even if we had some magical material that could withstand the required forces, we would eventually run into another problem:

There simply wouldn't be enough paper surface left to perform the next fold in the ordinary way.

The thought experiment quietly ignores all of this.

And that's perfectly fine.

Its purpose isn't to tell us how to build a lunar ladder out of office paper.

Its purpose is to make exponential growth intuitive.

The real lesson is not about paper

The paper is just an example.