Predictions of uncertain events are often described in terms of what can or what will happen. How are such statements used by speakers, and what are they perceived to mean? Participants in four experiments were presented with distributions of variable product characteristics and were asked to generate natural, meaningful sentences containing either will or can. Will was typically associated with either low or intermediate numeric values, whereas can consistently suggested high (maximum) values. For instance, laptop batteries lasting from 1.5 to 3.5 hours will last for 1.5 hours or for 2.5 hours, but they can last for 3.5 hours. The same response patterns were found for positive and negative events. In will-statements, the most frequent scalar modifiers were at least and about, whereas in can-statements, the most frequent modifier included up to. A fifth experiment showed that will indicates an outcome that may be certain but more often simply probable. Can means possible, but even can-statements are perceived to imply probable outcomes. This could create a communication paradox because most speakers use can to describe outcomes that because of their extremity are at the same time quite unlikely. Copyright © 2011 John Wiley & Sons, Ltd.