Well, let's do a back of the envelope calculation right here, how about that?
Antartica is - famously - a continent with a giant ice glacier on top of it. That shouldn't be news to you. It's not an iceburg. Land mass of Antarctica clocks in at 14.2 million square kilometers and average depth of the ice is 2.16 km. These are just averages I pulled from wikipedia, of course, so in actual climate studies there's going to be some squabbling over which numbers should be used - the depth of the ice depends on the time of year, and here I'm assuming that the ice density is going to be uniform throughout the depth which of course it isn't - but again, for a rough ballpark guesstimation, we have volume of ice in Antarctica at about 30.67 million cubic kilometers.
That has to be converted to volume of sea water as - again, famously - the density of sea ice is significantly less than the density of sea water. Again, the methodology here glosses over a massive amount of arguing because Antarctic glacier ice is not iceburg sea ice. But again, for our purposes, let's use 917 kg per cubic meter for ice and 1023.6 kg per cubic meter for sea water. So what we're adding into the oceans here is 34.2 million cubic kilometers.
Surface area of the ocean is 361 million square kilometers. Remember that Antarctica is still a continent at this point just with less ice on it; again, we could argue about the methodology for modelling how much land will be submerged by ocean here, but if we divide our 34.2 million of water over 361 million of ocean floorspace, we guesstimate a ballpark depth of ocean to be 0.0948 km or 94.8 m.
Which is actually WORSE than what I posted. The number I got was from a more rigorous study using much more pinned down numbers, and they estimate that a melted Antarctic would ONLY raise the oceans by 60m. THAT'S A LOW-BALL ESTIMATE, not a high one.
"Considering the square footage of water on the Earth".... what about it? There's not enough detail in your comment to pinpoint what your confusion is. Are you underestimating the amount of ice sitting on Antarctica? Is that your misconception?