People in high-income countries underestimate their affluence relative to the global population, potentially limiting their will- ingness to donate to charity. We test whether a rank-based nudge (RBN) informing individuals how their post-tax income ranks globally increases charitable donations. Further, because people have been shown to shift their reference point for who should give to charity based on their current income, we inves- tigate whether donations can be boosted by asking how much people with different income ranks should give to charity (in- junctive distribution task, IDT) before administering the RBN. Participants (N = 1,217) were randomly assigned to one of four conditions: control, RBN, IDT, or IDT+RBN. Those in the RBN conditions donated significantly more and reduced over- estimation of others’ income across all percentiles of the global income distribution. However, the addition of the IDT did not further increase donations. These findings suggest that RBNs effectively boost generosity by correcting misperceptions of relative affluence.