 Acrocanthosaurus was among the largest theropods known to exist . The largest known specimen ( NCSM 14345 ) is estimated to have measured 11 @.@ 5 m ( 38 ft ) from snout to tail tip and weighed 5 @.@ 7 t ( 6 @.@ 3 short tons ) to 6 @.@ 2 t ( 6 @.@ 8 short tons ) , with an upper maximum weight of 7 @.@ 25 t ( 7 @.@ 99 short tons ) within the realm of possibility for this specimen . Its skull alone was nearly 1 @.@ 3 m ( 4 @.@ 3 ft ) in length . 
