What percentage of the Earth's hydrosphere is made up ocean water?

71% of the earth's surface is covered by water.

Oceans cover the largest percentage of the earth's water areas.

Body of Water & Percentage

Pacific Ocean 46%

Atlantic Ocean 24%

Indian ocean 20%

Arctic Ocean 3%

Other Waters 7%

(Lakes, bays, seas, canals and other water masses are the remaining 7%)

However in terms of mass, the water only accounts for 0.023% of the Earth's 5.9736 x 1024 kg mass.