How many miles wide is mercury?

Answer 1

-- Mercury the planet is very nearly a sphere, with diameter 4,880 km (3,032 miles).

-- Mercury the element is a liquid at room temperature, and spreads to occupy the width
of whatever container it's in.

(Don't try this at home. Mercury the element is poisonous.)

Answer 2

Mercury is about 3,032 miles wide. It is the smallest planet in our solar system.