The G3 battlecruisers were a class of battlecruisers planned by the Royal Navy after the end of World War I in response to naval expansion programmes by the United States and Japan. The four ships of this class would have been larger, faster and more heavily armed than any existing battleship (although several projected foreign ships would be larger). The G3s have been considered to be proper "fast battleships" since they were well-balanced designs with adequate protection. Nonetheless the class was officially designated as a "battlecruiser" due to their higher speed and lesser firepower and armour relative to the planned N3-class battleship design. The G3s carried nine 16-inch (406 mm) guns and were expected to achieve 32 knots (59 km/h; 37 mph), while the N3s would carry nine 18-inch (457 mm) guns on the same displacement at the expense of a slower speed.