Inventory recording is critical for business players, not only for giant corporations but also for micro, small, and medium enterprise (MSMEs). A thorough record of entering and exiting items can reduce errors, streamline work procedures, and make future investment decisions easier. However, due to limited human resources in information technology, MSMEs may continue to keep records manually. Store N, a costume rental MSME, also encountered a similar issue. Business owners need help keeping track of the rotation of costumes, especially at certain events. This research aims to create a web-based store inventory information system to help store N launch its business. The recording of purchases, rentals, returns, and costume conditions is performed centrally in a database. The method used in this research is the System Development Life Cycle (SDLC) with the Waterfall model, because each process is clearly defined and easy to understand. The research results found that this system functions properly, speeds up employees serving customers, and makes it easier for owners to monitor business activities and allocate funds appropriately to procure new costumes.