Normally, the capacity of the bladder is about 400 ml. The bladder is a storage organ for urine, and too little or too much capacity can have an impact on the patient’s urination and kidney function. For some people, the bladder is in a semi-filled state as it is unable to fill to its normal capacity due to overactivity caused by work. Patients may develop strong signals to urinate, leading to frequent and urgent urination. If there is bladder tuberculosis, resulting in bladder contracture, then the bladder capacity is significantly reduced. In patients with BPH, the bladder capacity gradually increases due to bladder outlet obstruction, mainly due to dysuria, leading to increased residual urine. A large amount of urine cannot be excreted from the bladder and the bladder is in a state of chronic dilatation. In general, a decrease or increase in bladder capacity is considered abnormal and should be treated promptly.