When does giving lead to happiness? Here, we present two studies demonstrating that the emotional benefits of spending money on others (prosocial spending) are unleashed when givers are aware of their positive impact. In Study 1, an experiment using real charitable appeals, giving more money to charity led to higher levels of happiness only when participants gave to causes that explained how these funds are used to make a difference in the life of a recipient. In Study 2, participants were asked to reflect upon a time they spent money on themselves or on others in a way that either had a positive impact or had no impact. Participants who recalled a time they spent on others that had a positive impact were happiest. Together, these results suggest that highlighting the impact of prosocial spending can increase the emotional rewards of giving.