18%
If by land mass you mean the surface, then 99% is habitable.
60
15 percent of land
About 85 percent, namely all water surfaces (70%) and many of the mountain and desert areas on dry land.
75 percent
land that you can live on:)
It's about 25-30 percent land.
About 71 % of the surface is covered by water. The rest (29 %) is land.
About 29.2 percent of the Earth's surface is land, 13.3 percent of which is at least somewhat arable. That leaves about 54.4 percent of the surface land that is at least somewhat inhospitable.
The Earth is covered with 71 percent by oceans. The oceans hold close to 97 percent of all Earth's water.
We use about 38 percent of Earth's land surface for agriculture.
All land combined covers about 30% of Earth's surface.