Studies show that, although many people are concerned about the potential health risks of being exposed to electromagnetic fields (EMF), lay understanding of exposure, an important determinant of risk perceptions and responses, is limited. In an online consumer panel (n = 245), we tested the effects of providing people with information about EMF on lay understanding of exposure, and on perceptions and responses to risks, using an experimental 2 × 2 × 2 design. Providing people with specific information explaining the distance–exposure relationship, clarifying EMF policy, or specifying personal exposure management options actions resulted in a better understanding of exposure. We demonstrated that information provision as such had no effects on concerns about EMF nor on perceived risk of personal sources, i.e. mobile phones, but lowered perception of risk of public sources, i.e. mobile phone base stations and high-voltage power lines. In addition, information explaining the distance–exposure relationship in combination with policy information resulted in reduced self-reported risk-aversive responses. Moreover, participants who understood more about exposure in relation to the distance to the source showed lower perceptions of risk, were less likely to restrict their own exposure, and more likely to accept new installations of public sources of EMF in their neighborhood. In contrast, awareness that exposure was mainly determined by personal use of EMF sources corresponded with higher perceptions of risk from personal sources and a higher likelihood to restrict one’s own exposure. Our findings provide focal points for improving communication on EMF. In particular, we suggest to include information clarifying the distance–exposure relationship to improve understanding of exposure.