RamBal is an easy-to-use, Excel-based tool for material balance calculations to help predict future performance of abnormally pressured, unconventional gas fields. The algorithm compensates for reservoir rock and water compressibility in determining both OGIP and recoverable reserves and accounts for finite downdip free water expansion. The program requires only commonly available reservoir pressures, temperature data and gas properties and includes "calculators" and tips to help experienced petroleum professionals assess appropriate compressibility coefficients as well as the conversion of separator gas components to reservoir (wet gas) conditions. A user's manual is included in an Excel file accessible from the engineering menu. As is the case with all posted freeware, the material balance application produces presentation-quality, on-screen views and printer-friendly, hard-copy output.