How much of an iceberg rises above the waterline?

The common perception that only one-tenth of an iceberg rises above the waterline is a generalization; the actual proportion depends on the density of the ice and the presence of trapped air.

Because ice is less dense than liquid water, it floats according to Archimedes’ principle, which states that the buoyant force is equal to the weight of the displaced fluid. While pure ice has a density of approximately 920 kg per cubic meter, the upper portions of an iceberg—often composed of firn or compressed snow—can have a significantly lower density, sometimes as low as 400 kg per cubic meter.12

As an iceberg drifts and its surface melts, its structural composition and density profile change, which can alter its buoyancy and stability. Consequently, the ratio of the iceberg's "freeboard" (the portion above the water) to its "draft" (the portion below the water) is not a fixed constant but varies based on the specific physical properties and age of the ice.23