| Sg | Pl | |
| Nom | jarl | jarlar (rule) |
| Acc | jarl (rule) | jarla (rule) |
| Dat | jarli (rule) | jörlum (rule) |
| Gen | jarls (rule) | jarla (rule) |
| Sg | Pl | |
| Nom | jarlinn (rule) | jarlarnir (rule) |
| Acc | jarlinn (rule) | jarlana (rule) |
| Dat | jarlinum (rule) | jörlunum (rule) |
| Gen | jarlsins (rule) | jarlanna (rule) |