NexSample

NexSample is a free sample size calculator for clinical research, designed for medical residents, fellows, postgraduate students, and researchers. It includes 26 calculators covering the most common study designs in clinical trials, observational research, and diagnostic studies, along with calculators for agreement, reliability, and regression that are hard to find elsewhere. Whether you are planning a thesis, protocol, dissertation, grant proposal, or manuscript, NexSample helps you calculate sample size quickly and accurately, with full formulas and references shown for every calculation.