A furlong is a unit of length in the US customary and imperial sytems of measurement. The name is derived from the historical use of the furlong to refer to the average length of the furrow in 1 acre of a ploughed field, hence the name "furrow-long." 1 furlong is equal to:

Definitions of the furlong

The definition of the furlong differs slightly depending on whether it is defined based on the international yard or the US survey foot. The international yard is defined as 0.9144 meters. The US does not formally define survey yards, but based on the survey foot, which is equal to 0.30480061 meters, the "survey yard" is 0.91440183 yards.

Practically, the difference in measurement in the furlong based on the difference between the international yard and survey foot is too small to result in significant consequences. Since survey measurements typically involve very large areas with variable conditions anyway, the best reported survey data is expected to have some degree of inaccuracy that would not really be distinguishable from any inaccuracy resulting from the minor difference in definitions of the furlong.

Since the furlong is no longer widely used, it can be useful to be able to convert from furlongs to more widely used units of measurement.


Convert 72 furlongs to feet and meters.

1. 72 × 660 = 47,520 feet

2. 72 × 201.168 = 14,484.096 meters

3. 72 × 201.1684026 = 14,484.125 meters

There is a 0.029 m difference based on the international yard definition definition (2) and the survey foot definition (3) of the furlong.

Did you know?

The furlong is no longer commonly used, except in horse racing in English-speaking countries. Its use in horse racing is mostly due to tradition; when horse racing was first formalized in the 1500s, the furlong was the unit of choice, and this has not changed in most English-speaking countries where horse races are held.

The Kentucky Derby, the world's most famous horse race, is held on the first Saturday of May each year at the Churchill Downs in Louisville. It is a 10-furlong race (1 miles) for 3-year-old horses.