The average density of the Sun is about 1.4 grams per cubic centimeter (1.408 g/cm³). This means that, averaged across its enormous volume, a cubic centimeter of solar material would have about 1.4 times the mass of a cubic centimeter of water.
The figure is calculated from the Sun's total mass and volume, not measured from a uniform sample. The Sun is a sphere of extremely hot plasma, and its density changes dramatically with depth. Its outer layers are very diffuse, while the core reaches roughly 150 g/cm³, where immense pressure enables hydrogen fusion.
A common mix-up is confusing the Sun's average density with Earth's. Earth averages about 5.5 g/cm³ because it contains a large proportion of dense rock and metal. Despite the Sun's huge mass—about 333,000 Earth masses—its vast volume makes its average density comparatively low. The Sun's density is also slightly greater than water, although the Sun is not solid or liquid in the ordinary sense.