"Breadth" usually refers to the width or distance across something. Earth is a sphere, so it doesn't have a single, fixed breadth. However, we can talk about different ways to measure its width:

* Equatorial Diameter: This is the widest point across Earth, measuring approximately 12,756 km (7,926 miles).

* Polar Diameter: This is the distance across Earth through the poles, measuring approximately 12,714 km (7,900 miles).

So, depending on what you mean by "breadth", Earth's width can range from 12,714 km to 12,756 km.