Technically, Allure of the Seas is slightly larger than its sister ship, Oasis of the Seas, although they were built to the same general specifications. When Allure of the Seas was measured after its launch, it was found to be approximately 50 millimeters (about 2 inches) longer than Oasis. While this difference is negligible and was likely the result of small temperature variations during the steel cutting and welding process in the shipyard, it was enough for Allure to officially claim the title of the world's largest passenger ship at the time. Both ships belong to the Oasis Class and share nearly identical gross tonnage (around 225,000 GT) and passenger capacities. Since their launches, they have both been surpassed by newer Oasis-class ships like Symphony and Wonder of the Seas, and more recently by the Icon of the Seas, which is currently the largest ship in the world.