2,971. How Big is a Chomer?

Hilchos Arachin Vacharamin 4:4

A chomer is the same as a kor (about 60 gallons), which is equal to two lesech. A lesech is 15 seah. Therefore, a kor is 30 seah, which is ten efah because an efah is three seah. It was discussed in Hilchos Shabbos that an area of 50 cubits by 50 cubits is called a beis seah because a seah of seed can be planted in it. Accordingly, an area of 75,000 square cubits, which is a square of approximately 274 cubits by 274 cubits, is called a beis kor because a chomer of barley can be planted in it.

Hilchos Arachin Vacharamin 4:5

The valuations of fields are calculated as followed: If someone consecrated an ancestral field with eight years remaining until yoveil (the Jubilee year), not including yoveil itself as we have said, then one who wants to redeem it from the Temple treasury must pay eight sela and eight pundiyon for each area in which a chomer of barley can be planted. If the owners want to redeem it, they must pay ten sela and ten pundiyon because owners who redeem fields add a fifth. Whenever the Torah mentions a fifth, it means that the principal plus the additional amount will equal five parts, i.e., he adds one-quarter of the principal amount. [Example: if the principal is 80, one would add 20. This is 25% of the principal but one-fifth of the total.] If the wife or heirs of the one who consecrated the field redeems it, they must likewise add a fifth.