This is an instruction manual for the aerodynamic lens design tool: the "Aerodynamic Lens Calculator". We explain how to install and use this software. Examples are provided to use this tool to design or test a lens system. The structures of the source code programming are also provided in this manual. The design tool and its manual mentioned in this article are available in the publisher's online edition of Aerosol Science and Technology. To access this file, click on the link for this issue, then select this article. In order to access the full article on-line, you must either have an institutional subscription or a member subscription accessed through www.aaar.org.