Nail (unit)

Nail (unit)

A nail, when used as a unit, is usually one sixteenth of a certain base unit. In English usage the most common base units were the foot and the yard for length, the acre for area and the (long) hundredweight for mass.

Nails
Base unit Equivalent Metric
foot 1 digit = ¾ inch = 1.905 cm
yard 2¼ inches = 5.715 cm
acre ¼ rood = 10 square rods = 252.9285264 m²
hundredweight 1 clove = 7 pounds = 3.17514659 kg

(Metric sizes calculated for most common values of the base units today.)