What Is a Furlong?
A furlong (abbreviated fur or f) is a unit of length equal to 220 yards, 660 feet or one-eighth of a mile, which is exactly 201.168 meters. In surveyors’ terms it is 10 chains or 40 rods. It is still a legal unit in the US customary system and appears with its exact metric value in NIST Handbook 44.
The name is Old English: furh (furrow) and lang (long). A furlong was the length of a furrow that a team of oxen could plow before resting and turning, the standard length of a strip in the open fields of medieval England. An acre was originally the area of one furlong by one chain, the land an ox team could plow in a day, which is why an acre is still exactly 4,840 square yards: 220 × 22.
The furlong has outlived the open fields in two places. Horse racing in the UK, Ireland, the United States and several Commonwealth countries uses it for race distances. And some city grids still follow it: in Chicago, eight standard blocks make a mile, so each block is about a furlong.
What Is a Mile?
The furlong is the reason the mile is 5,280 feet. The Roman mille passus, a thousand paces, was about 5,000 feet, but English farmland was laid out in furlongs. A 1593 Act of Parliament under Elizabeth I resolved the mismatch in favor of the furlong, declaring “a Mile to contain eight Furlongs, every Furlong to contain forty Poles, and every Pole to contain sixteen Foot and a half”. That makes 8 × 40 × 16.5 = 5,280 feet.
The international mile used today keeps that statute length and pins it to the meter. Since the International Yard and Pound Agreement of 1959, the mile has been exactly 1,609.344 m, and a furlong exactly one-eighth of that.
Famous Horse Race Distances in Miles
Race cards in Britain and the US still state distances in miles and furlongs, sometimes with extra yards. Races in France, Australia and much of the world use meters, which convert to about 201 m per furlong. The table converts some well-known races to miles.
| Race | Furlongs (fur) | Miles (mi) |
|---|---|---|
| Typical sprint (5 furlongs) | 5 | 0.625 |
| Preakness Stakes | 9.5 | 1.1875 |
| Kentucky Derby | 10 | 1.25 |
| Breeders' Cup Classic | 10 | 1.25 |
| Prix de l'Arc de Triomphe (2,400 m) | 11.93033 | 1.491291 |
| Belmont Stakes (traditional distance) | 12 | 1.5 |
| Epsom Derby (1 mi 4 f 6 yd) | 12.02727 | 1.503409 |
| Melbourne Cup (3,200 m) | 15.9071 | 1.988388 |
The three US Triple Crown races increase in length: the Kentucky Derby at 10 furlongs (1.25 miles), the Preakness at 9½ furlongs (1.1875 miles) and the Belmont Stakes, traditionally run over 12 furlongs (1.5 miles) and nicknamed the “Test of the Champion”. In England, the Epsom Derby has been run over about a mile and a half since 1784.
Racing speed is often described in seconds per furlong. A pace of 12 seconds per furlong is 0.125 miles every 12 seconds, or about 37.5 mph, and top horses can sustain faster fractions than that over a short distance.
Not every racing country kept the furlong. Australia converted its racing to metric distances in 1972, so the Melbourne Cup, once run over 2 miles, became 3,200 m, about 1.988 miles, roughly 20 yards short of the old distance. British and American racing still advertise races in furlongs, and betting form guides list a horse’s best distances the same way.
The furlong also appears in a famous joke unit. In the “furlong-firkin-fortnight” system, a speed of one furlong per fortnight is about 1 centimeter per minute, roughly the pace of a slowly growing plant. Physics teachers use it to show that any unit of length divided by any unit of time is a valid speed.
How Many Furlongs in a Mile?
There are exactly 8 furlongs in a mile, so converting miles to furlongs is a multiplication by 8. A quarter mile is 2 furlongs, a 5K is 24.9 furlongs, and a marathon is about 210 furlongs. Each furlong is exactly 10 chains, so a mile is also 80 chains. For walkers, a furlong is roughly 260 average steps, about two and a half minutes at a normal pace.