Whether or not someone turns out to vote depends on their beliefs (such as partisanship or sense of civic duty) and on friction—external barriers such as long travel distance to the polls. In this exploratory study, we tested whether people underestimate the effect of friction on turnout and overestimate the effect of beliefs. We surveyed a representative sample of eligible US voters before and after the 2020 election (n = 1,280). Participants’ perceptions consistently underemphasized friction and overemphasized beliefs (mean d = 0.94). In participants’ open-text explanations, 91% of participants listed beliefs, compared with just 12% that listed friction. In contrast, turnout was shaped by beliefs only slightly more than friction. The actual belief-friction difference was about one-fourth the size of participants’ perceptions (d = 0.24). This bias emerged across a range of survey measures (open- and close-ended; other- and self-judgments) and was implicated in downstream consequences such as support for friction-imposing policies and failing to plan one’s vote.