Sample Size Calculator

Choose a research method, adjust the parameters, and get an evidence-based sample size recommendation with academic citations.

Research method

Parameters

User segments

Prototype fidelity

Task complexity

Recommended sample size

participants

CALCULATIONBase: 5 = 5

Nielsen & Landauer (1993): 5 users find ~85% of usability issues. Virzi (1992) confirmed diminishing returns beyond 5. Per-segment minimum holds because issue discovery resets across distinct user populations.

Nielsen, J. (1993). Usability Engineering. Academic Press.