The calculator worksheet has been adapted from the downloadable spreadsheet, originally provided by the Massachusetts Library Association and then adapted for the web by Chelmsford Public Library. Maine State Library added extra accessibility coding and reformatting for ease of reading online. This spreadsheet requires either Microsoft Excel or the Excel Viewer. Thanks to all the contributing libraries.

For more information

• How these figures were calculated
• How to customize and use on your local library web site.
• Feel free to link to this calculator for patrons where ever your library is or use yourself with acknowledgement as we did.