Massachusetts Section 50 Interest Calculator — 3/09 is a tool used to calculate the interest owed on a delinquent tax debt for the state of Massachusetts. It is designed to help people calculate the interest owed on unpaid tax debt for a period of three months, from December 1, 2008, to March 1, 2009. The calculator is available as an online tool, as well as a downloadable Excel spreadsheet. The online calculator can be used to calculate the interest owed on one or more tax debt items, while the downloadable Excel spreadsheet allows users to calculate interest owed on multiple tax debt items simultaneously. Massachusetts Section 50 Interest Calculator — 3/09 is available free of charge from the Massachusetts Department of Revenue website.