I don't think that this is technically true, since icebergs are made from fresh water and they melt in the salt water of the ocean. Fresh water is less dense, so it will take up a larger volume than that of salt water.
From what I remember reading, if all of the floating sea ice on the globe were to melt right now, sea levels would rise by about 5 centimeters.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...