Using the Waters AutoPurification System, separation methods can be developed on an analytical scale and transferred to preparatory scale on the same system, reducing a laboratory's overall capital investment. Here we illustrate a systematic approach to scale-up using the separation of Kudzu (Pueraria lobata) root extract to move from a 4.6 mm I.D. analytical column separation through 10, 19, and 30 mm I.D. preparatory column separations. The Waters OBD Prep Calculator is featured.