| Postmast | Nominativ, Singular | nominative case, singular | |
| Postmaste | Genitiv, Singular | genitive case, singular | |
| Postmasten | Dativ, Singular | dative case, singular | |
| Postmast(e)s | Akkusativ, Singular | accusative case, singular | |
| Postmaster | Nominativ, Plural | nominative case, plural | |
| Postmastern | Genitiv, Plural | genitive case, plural | |
| Postmastn | Dativ, Plural | dative case, plural |