The bladder capacity can be 300-500ml under normal circumstances. An overactive bladder may have urinary retention, resulting in a large amount of residual urine in the bladder. When bladder capacity is reduced, with more frequent urination and very little urine at a time, this may be due to inflammation of the bladder, overactive bladder disorder, or a tuberculous bladder resulting in bladder contracture. Bladder capacity is one of the simplest and most effective criteria for assessing bladder function. Excessive and small bladder capacity are both signs of a pathology, and under normal circumstances each urine output should be greater than 200 ml or more for effective urination. When it is necessary to hold urine, the bladder can hold up to 500ml. if there is still urine volume in the bladder after urination, this is an obstruction at the bladder outlet.