What is the thickness of the Earth's inner core?

The thickness of the Earth's inner core is approximately 1,220 kilometers (about 760 miles). The inner core is solid and primarily composed of iron and nickel. It lies beneath the outer core and extends from a depth of about 5,150 kilometers (3,200 miles) to 6,370 kilometers (3,960 miles) from the Earth's surface. The inner core experiences extreme temperatures, reaching up to 5,700 K (5,427 °C or 9,800 °F), and the immense pressure at these depths keeps it in a solid state despite the high temperatures. The study of the inner core is crucial to understanding the Earth's geodynamics and magnetic field generation.