Most historical estimates say the Titanic’s iceberg was roughly 50–100 feet (about 15–30 meters) high above the water and around 200–400 feet (about 60–120 meters) long along the waterline, based on survivor and witness accounts. Since only about one-tenth of an iceberg’s mass is visible above the surface, that suggests a total depth of roughly 90–185 meters and a mass on the order of a couple of million tons.