Numbers are from web searches and rounded.
Area of Greenland ice sheet 660235 Sq Mi.
Average thickness of Greenland ice sheet 0.95 Mi
Ice volume 660238 Sq Mi x 0.95 Mi = 627223 Cu Mi
Density convert ice to water 627223 Cu Mi x 0.9 = 564500 Cu Mi
Area of earths oceans 1.4 x10(8) Sq Mi
Sea level rise 564500 / 1.4 x10(8) = 0.004 Mi
Mi to feet 0.004 Mi =21 Ft
That would be a vertical rise, that does not take into account sloped shore lines and water level rise in river deltas, so the ocean rise would be less. Some one else needs to figure that out.
I ran the calculation a few years ago. I worked with the current area of the oceans with the new volume of ice melt on top. I got a nine meter rise, which is in the vicinity of 27 feet. I didn't figure the volume of the space surrounding the oceans; however, a 27 foot rise does not go very far inland in most places.
Florida would be completely submerged, and New Orleans wouldn't need to worry about hurricanes any longer.
Seacoast cites the world over would be gone.
Now, those alarmist folks need to consider a few things. Greenland is a really big place where most of the ice mass is way north. Temperatures have not ever risen anywhere near the melting point. The higher temperatures experienced in the southern regions really are not so unusual. Remember, the Vikings called the place "Greenland" because it surely was when compared to Norway.
That ice sheet isn't going anywhere for a very long time. I read somewhere that the southern portion of the sheet is getting thinner while the northern region is getting thicker.