Largest conventional bomb by weight

The heaviest conventional bomb ever used operationally was the Royal Air Force's Grand Slam, weighing 9,980 kg (22,002 lb) and measuring 7.74 m (25 ft 4 in) long, which was first dropped on Bielefeld railway viaduct, Germany on 14 March 1945. In all, 41 Grand Slam bombs were dropped by 617 Squadron RAF in 1945. In 1949 the United States Air Force tested a bomb weighing 19,050 kg (41,998 lb) at Muroc Dry Lake, California, USA. Grand Slam was developed by Barnes Wallis (UK) of bouncing bomb fame.