This document outlines demand forecasting methods for supply chain planning. It discusses the role of forecasting in production scheduling, inventory management, sales planning and other supply chain functions. Several forecasting techniques are described, including qualitative, time series and causal methods. Time series methods use historical demand patterns to forecast future demand. The document explains how to decompose time series data, estimate trend and seasonal factors, and generate forecasts. Measures of forecast accuracy like mean squared error, mean absolute deviation and mean absolute percentage error are also defined. An example of demand forecasting for Tahoe Salt is presented to illustrate the techniques.