Pengembangan Sistem Informasi Penjualan Obat Berbasis Web dengan Prediksi Kebutuhan Stok Menggunakan Metode Moving Average pada Toko Obat Azka Cengkareng Jakarta Barat

This study develops a web-based medicine sales information system with sales forecasting for Azka Pharmacy in Cengkareng, West Jakarta. The existing process relied on manual recording and rekapitulation, making it difficult to use historical sales data as a basis for planning future inventory. The research uses a qualitative descriptive approach with observation, interviews, and literature study. System development follows the Waterfall model covering requirements analysis, system design, implementation, testing, and maintenance. The system is implemented using PHP, MySQL, XAMPP, HTML, CSS, and JavaScript, while UML is used for system modeling. The application provides login, product and category management, purchase transactions, sales transactions, actual sales data, forecasting, and reporting. The forecasting module applies the Single Moving Average method using historical sales data. In the PARACETAMOL example, a moving-average setting of three is used and the forecast for period 13 is 540 units. Forecast evaluation is presented using error, cumulative error, Mean Absolute Deviation (MAD), and Tracking Signal. The resulting system provides structured sales and inventory information and supports planning of future medicine stock.