The increase in prostate volume could be measured in each 10-year age group and doubled, from 5.5 ml in 40 to 49 years to 11.1 ml in 70 to 80 years. A normal-sized prostate weighs about 25 grams, about the size of a walnut. However, an enlarged prostate can grow more than three times the normal size (more than 80 grams). The size of a man's prostate varies from person to person.
Size is just one of the many factors we consider when determining if a man needs treatment for BPH. If medications don't work or the prostate is too large, surgery will often remove enough of the prostate to provide relief. An enlarged prostate can weigh up to 100 grams or more (about the size of an orange or a small grapefruit) and is more likely to cause urinary problems.