People who believe they have greater control over health and longevity are typically more likely to invest in their long-term health. Investigating individual differences in perceived control over risk, and exploring different determinants of health effort, may help to tailor health promotion programmes to more effectively encourage healthy behaviours. From a sample of 1,500 adults, we measured perceived control over 20 causes of death, overall perceived uncontrollable mortality risk (PUMR), state-level optimism, self-reported health effort, and accuracy of estimations of avoidable deaths. We found individual differences in perceptions ofcontrol over specific causes of death based on age, gender and income. PUMR was predicted by socioeconomic variables expected to influence exposure to risk and resource availability. Higher levels of PUMR, not perceptions of control over specific causes of death, predicted self-reported health effort. The strength of relationship between PUMR and lower health effort was not moderated by state-level optimism. Age and education both positively predicted greater accuracy in assessing the prevalence of avoidable deaths. We suggest that PUMR may capture people’s ‘general sense’ of mortality risk, influenced by both exposure to hazards and the availability of resources to avoid threats. Conversely, perceived control over specific risks may involve more deliberate, considered appraisals of risk. This general sense of risk is thought to play a more notable role in determining health behaviours than specific assessments of control over risk. Further study is needed to investigate the degree to which PUMR accurately reflects objective measures of individual risk.