A method and system are provided for forecasting keyword search volume. Keywords are categorized by concept and by the amount of data available for use in predicting future behavior. The keywords and/or the categories can also be categorized as seasonal or non-seasonal. A category level seasonal variation pattern can then be calculated based on keywords in the category that have sufficient historical data. A search volume can then be predicted for one or more keywords, with an appropriate calculation algorithm being selected based on the concept category, seasonal classification, and historical data available for the keywords.