In recent years, ultrasonography (US) has become a popular alternative to computerized tomography (CT) for renal calculi, which is the gold standard. The US is easy to use and cheaper. This study compares ultrasonography to CT scans, which are considered the most accurate method for detecting kidney stones, their size, and their position. A cross-sectional urology outpatient clinic study was done. In the study, 52 patients aged 19–81 with flank pain were suspected of having renal stones. After demographic data, a thorough history, a routine abdominal exam, and laboratory tests, patients had abdominal ultrasounds to confirm renal stones. If the results were positive, the stone size, position, hydronephrosis, and severity were documented. Following that, the patients were instructed to do a very low-dose native CT scan of the pelvis and abdomen to duplicate the information obtained from the US stone assessment. The original author, a five-year radiologist, reviewed both techniques. The US and CT have a kappa score of 0.338, indicating a fair agreement on stone location. To clarify, the US was insensitive in the middle and upper calyx and missed seven stones, 13.46% of the total. The kappa value between the US and CT for hydronephrosis severity was 0.401, indicating some agreement. The ultrasound missed hydronephrosis in 11 of 18 cases (61.11%). Hydronephrosis in severe and moderate instances is most insensitively diagnosed by ultrasonography. US and CT stone size estimates were highly accurate (ICC > 0.9).