Conversion from Furlongs to Inches

Information about the Furlong (fur)

The furlong is a unit of length equal to 220 yards, 660 feet, or exactly 201.168 metres. It is one eighth of a mile and ten chains.

The name is a contraction of the Old English furh lang, meaning furrow long, and describes the distance a team of oxen could plough before needing rest. That practical origin fixed the length of a medieval strip field, and the furlong therefore predates the mile's English definition. When the Roman mile of 5000 feet was reconciled with English land measurement, the mile was lengthened to 5280 feet so that it would contain a whole number of furlongs. The awkward figure that generations of schoolchildren have memorised is a direct consequence of preserving the older agricultural unit.

Horse racing is where the furlong remains in active daily use. Race distances in Britain, Ireland, the United States and much of the racing world are stated in miles and furlongs, so a race described as one mile two furlongs covers 2010 metres. Sectional times are recorded furlong by furlong, and commentary is built around the unit. Distance markers along the rail count down the remaining furlongs to the finish.

The furlong's relationship to area explains its persistence in older records. An acre was originally defined as one furlong long by one chain wide, the area a team could plough in a day. This is why an acre is a long thin rectangle rather than a square, and why its modern value of 43,560 square feet looks arbitrary.

Outside racing the unit is largely archaic, though it appears in some historical land deeds and in the occasional legal description. Computing folklore keeps it alive in the furlong per fortnight, a deliberately absurd unit of speed used to make a point about dimensional analysis.

It is the reason the acre has the shape it does. An acre was defined as one furlong long by one chain wide, 220 yards by 22, and that long thin rectangle is exactly what a team of oxen could plough in a day without turning more often than necessary. The proportion of ten to one is preserved in the ridge and furrow patterns still visible from the air across the English Midlands, and in field boundaries that have outlasted every plough that made them. The furlong therefore survives less as a measurement than as a shape written into the landscape.

One furlong equals 220 yards, 10 chains, one eighth of a mile, or 201.168 metres.

Information about the Inch (in)

The inch is a unit of length equal to exactly 25.4 millimetres. It is one twelfth of a foot and one thirty-sixth of a yard. The symbol is in, though a double prime is common in technical contexts and a straight double quote is often substituted informally.

The name comes from the Latin uncia, meaning a twelfth part, which also gave English the word ounce. Early definitions were anatomical or agricultural. A statute of Edward II defined the inch as three barleycorns laid end to end, and the width of a man's thumb served as a working approximation in several European languages. Dutch and Swedish still use words for inch that mean thumb.

Its modern precision dates from 1959, when the International Yard and Pound Agreement fixed the yard at exactly 0.9144 metres across the United States, the United Kingdom, Canada, Australia, New Zealand and South Africa. Before that agreement the American and British inches differed very slightly, which mattered in precision manufacturing. The United States retained a separate survey inch for land measurement until it was formally retired at the end of 2022.

The inch remains dominant in several international industries regardless of local measurement systems. Screen sizes are quoted in inches worldwide, measured diagonally. Tyre rim diameters, bicycle wheel sizes, plumbing pipe bores and rack-mounted equipment all use inch designations, and the standard 19-inch rack is a global fixture. Photographic sensor sizes use inch fractions that no longer correspond to any real dimension, a survival from television camera tube measurements.

Subdivision is traditionally binary rather than decimal. An inch is halved repeatedly into eighths, sixteenths and thirty-seconds, which suits ruler markings and fits the fractional sizing of drill bits and spanners. Decimal inches are used in machining, where thousandths of an inch are called thou or mils.

Screens and printing keep it in daily use far outside the countries that use it for anything else. Televisions, monitors and phones are sold by the diagonal in inches everywhere, so a 55-inch television has the same name in Paris as in Chicago. Typography rests on the same base: there are 72 points to the inch, a convention inherited from the printing trade and written into every computer font system, and image resolution is quoted in dots or pixels per inch. Anyone laying out a page in a country that has been metric for a century is therefore working, without particular thought, in twelfths and seventy-seconds of an inch.

One inch equals 25.4 millimetres, 2.54 centimetres, or 0.0254 metres exactly.