Bleeding during endoscopic prostate surgery is often overlooked, and appropriate measurement techniques are rarely applied. We proposed a simple and convenient method for assessing the severity of bleeding during endoscopic prostate surgery. We determined the factors affecting bleeding severity and whether they affected the surgical results and functional outcomes. Records from March 2019 to April 2022 were obtained for selected patients who underwent endoscopic prostate enucleation through either 120-W Vela XL Thulium:YAG laser or bipolar plasma enucleation of the prostate. The bleeding index was measured using the following equation: irrigant hemoglobin (Hb) concentration (g/dL) × irrigation fluid volume (mL)/preoperative blood Hb concentration (g/dL) × enucleated tissue (g). Our research revealed that patients who underwent surgery employing the thulium laser, those aged over 80 years, and those with a preoperative maximal flow rate (Qmax) of more than 10 cc/s experienced less surgical bleeding. The patients' treatment outcomes differed depending on the severity of the bleeding. Enucleating prostate tissue was easier in the patients with less severe bleeding, who also had a lower risk of developing urinary tract infections and an improved Qmax.