An RP-HPLC method for quickly and accurately measuring simvastatin in pure and capsule dosage forms was quickly and accurately made. Guidelines from the International Conference on Harmonization (ICH) were used to make sure the procedure worked. 4.6 mm x 250 mm Arcus EP-C18 Arcus EP-C18, with KH2PO4 solution (0.05 M) and methanol (20:80 V/V), at pH 5, as a mobile phase, at a flow rate of 1 mL/min. The HPLC system used the 240 nm UV system to find out what was going on. In order to do the analysis, a 10-minute run time was utilized. The linear method was (R2 =0.9990) at concentrations of (2 to 10 µg/mL), this method was linear, precise (inter-day RSD values were less than 1%), accurate (Range Recovery was 95±112% to 98.382±0.101%), specific, and strong. It was based on linearity and regression to figure out the detection and quantification limits. They were 0.85 µg/mL and 2.01 µg/mL, respectively. The proposed technique was being tested to be correct, precise, and quick when it came to simvastatin in bulk and capsule dosages, so it was a good idea.