Library Use Value Calculator http://www.maine.gov/msl/services/calculator.htm The Maine State Library offers this handy tool which helps library patrons understand the monetary value of the library materials, programs, meeting rooms, computers, and reference services they use. Library Use Value Calculator http://www.maine.gov/msl/services/calculator.htm http://www.maine.gov/msl/services/calculator.htm The Maine State Library offers this handy tool which helps library patrons understand the monetary value of the library materials, programs, meeting rooms, computers, and reference services they use.