Improved Sample Size Calculator Website & New Calculators for Your Research


Since its launch in 2017, the Clinical and Translational Science Institute’s Sample Size calculator website ( has gained traction not only at UCSF, but nationwide – it had 300,000 sessions in the past year with users from 1,200+ universities.  It is the standard site used for UCSF courses, including Designing Clinical Research and the undergraduate medical education courses on Epidemiology, Biostatistics, and Population Science (EBPS). The website has recently gone through a redesign with added improvements based on user feedback as well as new calculators to help researchers.

“The site redesign should make it even more useful to clinical researchers. We have added many new calculators, a tool to help you find the right calculator, and a summary page that shows all the calculators on the site,” said Michael Kohn, MD, MPP, member of CTSI’s Study Design consultation unit (part of the Consultation Services program) and the Sample-Size website, and professor of Epidemiology and Biostatistics. 

Publishing CTSA Program Hub’s Name