TANKS is a user-friendly computer software program developed for use in estimating volatile organic compound (VOC) emissions from both fixed and floating roof storage tanks. TANKS is based on the emission estimation procedures presented in Chapter 7 of the Compilation of Air Pollutant Emission Factors, AP-42. The emission estimation procedures used as the basis of the TANKS program include the recent updates to the equations from the American Petroleum Institute (API) Bulletins, for which EPA has been granted noncommercial use. An electronic copy of the user's manual is included with the program to aid users in mastering the program's many features and options. TANKS can generate emissions for vertical and horizontal fixed roof tanks, internal and external floating roof tanks, and domed external floating roof tanks. TANKS can also estimate emissions from underground storage tanks. After the user provides specific information concerning storage tank construction and the stored liquid, the program produces a report estimating total VOC emissions. TANKS includes four internal databases which contain chemical, meterological, roof fitting, and rim seal data, which greatly enhance the usefulness of the program. TANKS also contains three alternative speciation options that allow the user to estimate individual component emissions of stored liquid mixtures. To accommodate facilities with large numbers of tanks, the program can generate either a single report for an individual tank or a batch report for a series of tanks.