A foot is a US customary unit of length equal to 12 inches, about the length of a standard school ruler. Its abbreviation is ft, and its plural is feet. There are 3 feet in a yard and 5,280 feet in a mile, and 1 foot is exactly 30.48 centimeters.
Twelve inches make a foot, three feet make a yard, and 5,280 feet make a mile.
Formal definition and notation
The (international) foot is a unit of length in the US customary system defined as exactly 0.3048meter. It is divided into 12 inches, so 1 in = 2.54 cm exactly, and 3 feet make 1 yard. Area in square feet uses 1 ft2 = 144 in2, and volume uses 1 ft3 = 1,728 in3.
A meter is the metric unit of length, a bit more than 3 feet: 1 m is about 3.28 ft.
Footvs.Yard
A yard is 3 feet, about the length of a long step. 1 yd = 3 ft = 36 in.
Quick check: 3 questions
Question 1 of 3
How many inches are in 4 feet?
Show answer and explanation
Answer: C.4 × 12 = 48. A adds 4 and 12, B multiplies by 10, and D is the number of inches in one foot.
Question 2 of 3
How many feet are in 7 yards?
Show answer and explanation
Answer: A. 1 yard is 3 feet: 7 × 3 = 21. B multiplies by 12 (inches per foot), C adds 7 and 3, and D gives inches.
Question 3 of 3
A student is 5 feet 9 inches tall. What is that in inches?
Show answer and explanation
Answer: B.5 × 12 + 9 = 60 + 9 = 69. A just writes the digits side by side, C adds 5 and 9, and D forgets the 9 inches.
Foot: frequently asked questions
How many feet are in a mile?
A mile is 5,280 feet. That is 1,760 yards, because 5,280 divided by 3 is 1,760. To change miles to feet, multiply by 5,280: half a mile is 2,640 feet. To change feet to miles, divide by 5,280: a 10,560-foot trail is 2 miles long.
How many centimeters are in a foot?
One foot is exactly 30.48 centimeters, or 0.3048 meter. That makes a foot a little shorter than a third of a meter. To change feet to centimeters, multiply by 30.48: 6 feet is 182.88 cm. For a quick estimate, use 30 cm per foot.
LengthLength is how long something is: the distance from one end of an object to the other. You measure it by counting equal units laid end to end with no gaps or overlaps, such as inches, feet, centimeters or meters. A new pencil is about 7 inches long.Measurement · Grade 1, Grade 2, Grade 3MeterA meter (m) is a metric unit of length equal to 100 centimeters. It is the base unit of length in the metric system, a little over three feet (about 3.28 feet). A doorway is about 2 meters tall, and 1,000 meters make a kilometer. To change meters to centimeters, multiply by 100.Measurement · Grade 3, Grade 4, Grade 5InchAn inch is a US customary unit of length equal to one twelfth of a foot, about the width of an adult thumb. Its abbreviation is in. Rulers split each inch into halves, quarters, eighths and sixteenths. One inch is exactly 2.54 centimeters, and 12 inches make 1 foot.Measurement · Grade 2, Grade 3, Grade 4YardA yard (yd) is a US customary unit of length equal to 3 feet or 36 inches. It is a little shorter than a meter: 1 yard is exactly 0.9144 meter. Yards measure fabric, rooms, gardens and the length of a football field, which is 100 yards between the goal lines.Measurement · Grade 2, Grade 3, Grade 4SquareA square is a quadrilateral with four equal sides and four right angles. It is a special rectangle and a special rhombus at the same time. For a square with side s, the perimeter is 4s, the area is s2, and each diagonal is s√2.Geometry · Kindergarten, Grade 2, Grade 3VolumeVolume measures the amount of space inside a three-dimensional figure, in cubic units such as cubic centimeters or cubic feet. You can find it by counting the unit cubes that fill the solid. For a rectangular prism, V = l × w × h; for any prism, it equals the area of the base multiplied by the height.Geometry · Grade 5, Grade 6, Grade 7NumberA number is an amount or value used to count, measure, order and compare. We write numbers with digits (7), words (seven) or other symbols, but the number itself is the amount: 7 dots, the word seven and the numeral 7 all show the same number. Numbers include whole numbers, fractions, decimals and negatives.Number System · Kindergarten, Grade 1, Grade 2SideA side is one of the straight line segments that form the outline of a polygon. Two sides meet at each corner, or vertex. A triangle has 3 sides and a square has 4, and adding the lengths of all the sides gives the perimeter.Geometry · Kindergarten, Grade 1, Grade 2MileA mile (mi) is a US customary unit of length for long distances, equal to 5,280 feet or 1,760 yards. One mile is about 1.61 kilometers, so it is longer than a kilometer. Road distances and speed limits in the United States use miles and miles per hour.Measurement · Grade 4, Grade 5, Grade 6CentimeterA centimeter is a metric unit of length equal to one hundredth of a meter, about the width of a fingernail. Its symbol is cm. There are 100 centimeters in 1 meter and 10 millimeters in 1 centimeter, and 1 inch equals 2.54 centimeters.Measurement · Grade 3, Grade 4, Grade 5HeightHeight is how tall something is: the distance from its bottom to its top, measured straight up and down. In geometry, the height of a shape is the perpendicular distance from a base to the opposite vertex or side, so it always meets the base at a right angle. Area and volume formulas use it.Measurement · Grade 2, Grade 5, Grade 6RemainderA remainder is the amount left over when one whole number does not divide another evenly. In 23 ÷ 5, four groups of 5 make 20 and 3 are left, so 23 ÷ 5 = 4 R 3. The remainder is always smaller than the divisor. A remainder of 0 means the division is exact.Operations · Grade 4, Grade 5, Grade 6Unit ConversionUnit conversion is rewriting a measurement in a different unit without changing the amount, such as writing 3 feet as 36 inches. You multiply by a conversion factor, a fraction equal to 1 such as 12 in1 ft. Converting to a smaller unit gives a larger number; converting to a larger unit gives a smaller number.Measurement · Grade 4, Grade 5, Grade 6PerimeterPerimeter is the total distance around a two-dimensional shape. To find it, add the lengths of all the sides. A rectangle with sides 5 and 3 has perimeter 5 + 3 + 5 + 3 = 16. Perimeter is a length, so it uses length units such as inches or meters, never square units.Geometry · Grade 3, Grade 4, Grade 5AreaArea is the amount of surface a flat shape covers, measured in square units. It counts how many unit squares fit inside the shape, which is why the units are squared. A rectangle’s area is length times width, so a 5 by 3 rectangle has area 15 square units.Geometry · Grade 3, Grade 4, Grade 5Metric SystemThe metric system is a system of measurement in which units are related by powers of 10. Its base units are the meter for length, the gram for mass and the liter for capacity. Prefixes name larger and smaller units: kilo- means 1,000, centi- means one hundredth and milli- means one thousandth, so 1 km = 1,000 m.Measurement · Grade 4, Grade 5, Grade 6