What is Venus's mean density in grams per cubic centimeter?

Venus’s mean density is 5.24 g/cm³.

That value comes from dividing Venus’s mass by its volume. Venus is a rocky terrestrial planet, and its density is close to Earth’s 5.52 g/cm³, despite Venus having about 81.5% of Earth’s mass and a diameter roughly 95% as large. The similarity suggests that both worlds contain substantial metallic cores surrounded by rocky mantles and crusts.

Density is an average for the whole planet, not the density of its atmosphere or surface rocks. Venus’s atmosphere is extremely dense and composed mostly of carbon dioxide, but it contributes very little to the planet’s total mass compared with the interior. The surface itself is also far hotter and under much greater pressure than Earth’s surface.

A common mix-up is confusing Venus’s density with Mars’s, which is about 3.93 g/cm³, or with the densities of the giant planets. Venus’s high density is one reason it is classified alongside Mercury, Earth, and Mars as a terrestrial planet.