Diameter, circumference, surface area, volume – compare Earth to other planets, moons, or even custom-sized spheres. Instantly visualize scale like never before.

How big is your world?

Earth isn't the biggest planet, but it's our only home. Use the Earth Size Calculator to explore its true dimensions – from pole-to-pole diameter (12,742 km) to total surface area (510 million km²). Then scale it up or down relative to Jupiter, Mars, or a fictional world of your choosing. Perfect for students, space enthusiasts, or worldbuilders.

Not all planets are created equal. See how Earth measures up.

[Calculate Now] – It's free

Earth diameter: 12,742 km Circumference: 40,075 km Surface area: 510.1 million km² Volume: 1.083 trillion km³ …compared to your custom size: [user input] Would you like a more technical, educational, or playful tone? I can adjust it for a kids' science site, a sci-fi worldbuilding tool, or a classroom resource.