Lan (Polish: łan ; German: Lahn; Latin: laneus) is an old unit of field measurement used in Poland. Since the 13th century, its value has varied from one location to another. A greater łan (also Franconian, King's, Old Polish) consisted of 43.2 morgs = 23 to 28 hectares. A lesser łan (Chełmno łan) was 30 morg ≈ 17,955 hectare.
The term eventually derives from German Lehen, "fee" (feudal land tenure).[1] [2] The term łan was also used to indicate an average size of a peasant's tenured farm. Łan was further subdivided into zagony ("belts") and further into skiby ("slices").
In medieval times the size of a łan was anywhere between 3 and 50 hectares, but from the 13th century to 1857 in Great Lesser Poland (with Podkarpacie), the Franconian Łan was consistently used.
| Miara(Unit) | Sążeń², (Viennese fathom²) | Łokieć² (Viennese ell²) | m2 | ||
| 1 morg (morgen) (= 0.5755 ha) | 3 | 1600 | 6439.02 | 5754.64 | |
| 1 miara (Unit) (= 19.18 are) | 533.33 | 2929.07 | 1918 | ||
| 1 sążeń² wiedeński (Viennese fathom) | 4.0237 | 3.6 | |||
| 1 łokieć² wiedeński (Viennese el²) | 0.9 |