What percentage of Earth’s mass is water?

Water makes up 0.02% of the Earth’s mass, within the 0% to .05% of the range.

Approximately 71% of the Earth’s surface is water with the other 29% consist of continents and islands. 96.5% of all the Earth’s water is contained within the oceans as salt water, while the remaining 3.5% is made up of freshwater lakes and frozen water locked up in glaciers and the polar ice caps. Of that fresh water, 69% of it takes the form of ice.

In terms of volume, all of the water on Earth works out to about 1.386 billion cubic kilometres (km³) or 332.5 million cubic miles (mi³) of space.

In terms of mass, scientists calculate that the oceans on Earth weigh about 1.35 x 1018 metric tonnes (1.488 x 1018 US tons), which is the equivalent of 1.35 billion trillion kg, or 2976 trillion trillion pounds. This is just 1/4400 the total mass of the Earth, which means that while the oceans cover 71% of the Earth’s surface, they only account for 0.02% of the planet’s total mass.