How many participants are needed for usability testing?

UX researchers and other project stakeholders often fervently debate the number of participants that are necessary for usability studies. At the core of this debate is often the tension between the usability professional’s desire for the best possible study and the business team’s desire to reduce time and expense.In summary, research suggests that from three to twenty participants can provide valid results, and a good baseline is between five and ten participants. In general, there should be more participants for more complex, highly critical projects; while fewer participants are necessary when testing more novel designs.