We address the optimal marginal source of financing shocks that raise fiscal needs in the presence of a maturity structure for nominal government debt, distortionary taxes, and sticky prices. We find: (1) the importance of innovations in current and expected inflation that revalue debt increases with both the average maturity and the level of debt; (2) an analytical trade off between inflation and output-gap stabilization as a function of debt maturity; (3) at current debt levels and maturity lengths in advanced economies, inflation would account for as much as 50 percent of marginal optimal financing; (4) maturity attenuates welfare losses from nominal rigidities.