It is estimated that 97 percent of all water in the world or over one quadrillion acre-feet (1,234 x 10¹⁵ cubic meters) is contained within the oceans. If Earth were a uniform sphere, this volume of water would cover Earth to a depth of 800 feet (244 meters).

If you melted all the ice in the world, how high would the oceans rise?

If you melted all the ice in the world, some 5.5 million cubic miles (23 million cubic kilometers) in all, the oceans would rise 1.7 percent or about 180 feet (60 meters), which is enough, for example, for 20 stories of the Empire State Building to be underwater.