| Sg | Pl | |
| Nom | kaupmaðr | kaupmenn (rule) |
| Acc | kaupmann (rule) | kaupmenn (rule) |
| Dat | kaupmanni (rule) | kaupmönnum (rule) |
| Gen | kaupmanns (rule) | kaupmanna (rule) |
| Sg | Pl | |
| Nom | kaupmaðrinn (rule) | kaupmennnir (rule) |
| Acc | kaupmanninn (rule) | kaupmennina (rule) |
| Dat | kaupmanninum (rule) | kaupmönnunum (rule) |
| Gen | kaupmannsins (rule) | kaupmannanna (rule) |