How Thick Is Earth? – The Simplest Breakdown

By | January 3, 2023

“How thick is earth?” This is a question I have always asked myself ever since I learned the world is like a floating ball. This is somehow funny but I was so eager to know the thickness of the world so that I will not dig a hole to burst the ball from the inside…LOL.

It might sound funny at first but I was very little then. It is very interesting to know that the earth is thousands and thousands of Kilometres thick.

Earlier I wrote an article about how long it will take to reach the center of the earth from the surface. I think it is quite an interesting read if you wish to know about the thickness of the world.

How thick is earth?

The earth is more of an onion than a ball. It comes in layers just like a bulb of onion when you split it. However, the layers of the earth are thicker than you can ever imagine.

How thick is earth

The image above is a graphical representation of how thick the earth is. The layers of earth are grouped into four major layers but within those layers, there are other layers.

We will take a proper look at the earth layer by layer to find how thick the earth is.


The Crust is the very first layer from the surface of the earth. It measures approximately 30 km in thickness. Its topmost surface is made up of silicic rockest and at its base, you will find some andesite and basalt rocks.

The Crust is the thinnest layer of the earth according to geological studies.

Upper Mantle and Lower Mantle

The Mantle is the thickest layer of the earth. There are two different layers coming together to form the Mantle.

There is the Upper Mantle which measures approximately 720 km in thickness. The Upper Mantle is made up of peridotite, eclogite, olivine, spinel, garnet, and pyroxene rocks at the top. Its base is made up of perovskite and oxides.

The Lower Mantle measures approximately 2,171 km in thickness. This layer is fully made up of magnesium and silicon oxides.

Outer Core

The Outer Core is one of the hottest and thickest layers of the earth. According to Hyperphysics, this layer fully made of iron + oxygen, sulphur, and nickel alloy measures approximately 2,259 km in thickness.

It is the last layer covering the main core which is believed to be at the center of the entire planet.

Inner Core

The Inner Core is at the center of the earth and it is also believed to be the hottest layer of the earth. It is also fully made up of iron + oxygen, sulphur, and nickel alloy.

This layer measures approximately 1,221 km in thickness and can reach temperatures of about 9,392° Fahrenheit.

How thick is the earth?

If you follow the article up to this point, you will realize the earth is approximately 6,401 km thick. This is way thicker for someone to just dig to the core within a few days, weeks, months or even years.

Humans have not dug to even past the Mantle yet. It is believed the deepest hole ever dug on earth barely reached passed 40,000 ft and it took many years to get to that depth.

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