1 ft | 12 inches | 3.048 dm (decimeters) | 30.48 cm (centimeters) | 304.8 mm (millimeters) | 0.3048 meters

1 in | 0.08333 ft 1 dm | 0.3281 ft 1 cm | 0.03281 ft 1 mm | 0.003281 ft 1 m | 3.281 ft

length

distance

width

height

thickness

depth

radius

diameter

wavelength

perimeter

characteristic length

circumference

position

breadth

arc length

displacement

radial distance

semi-principal axis length

atomic radius

angular wavelength

mean free path

Cartesian coordinate

displacement vector

UK imperial | UK nautical | US Customary System (USCS) | US customary length | US linear | US nautical | foot-pound-second (FPS) | international yard and pound agreement | Canadian

no case for continued use in modern scientific and technical work (SI Brochure, 9th ed., 2019, Chapter 4, p. 146)

Light travel time t in vacuum from t = x/c: | 1 ns (nanosecond)

Light travel time t in an optical fiber t = 1.48x/c: | 1.5 ns (nanoseconds)

Angular wavelength ƛ from ƛ = λ/(2π): | 0.04851 meters

Frequency ν of electromagnetic radiation in a vacuum from ν = c/λ: | 0.98 GHz (gigahertz)

Frequency ν of sound from ν = v/λ: | 1.1 kHz (kilohertz) | (assuming speed of sound ≈ 340 m/s)

Spectroscopic wavenumber ν^~ from ν^~ = 1/λ: | 0.033 cm^(-1) (reciprocal centimeters) | 0.033 wavenumbers

≈ (0.3 to 0.4) × length of an average human step ( 68.96 to 97.44 cm )

≈ (0.5 to 1) × length of a stride on an elliptical trainer ( 12 to 22 in )

≈ 3.6 × typical length of a credit card ( 85.6 mm )

≈ 5.6 × width of a typical credit card ( 53.98 mm )

≈ (1 to 3) × height of a stair riser ( 4 to 7 in )

≈ depth of a stair tread ( ≈ 10 in )

≈ 1.3 × inner radius of an NBA basketball rim ( 9 in )

≈ (0.8 to 1.4) × diameter of a typical flying disc ( 21 to 40 cm )

≈ 0.44 × sound wavelength at 500 Hz (fourth octave) in air at 21 °C ( ≈ 0.69 m )

≈ 0.9 × sound wavelength at 1000 Hz (fifth octave) in air at 21 °C ( ≈ 0.34 m )

≈ (0.9 to 2.5) × typical wavelength used by cell phones ( 12 to 35 cm )

≈ 1.1 × largest wingspan of an insect (white witch moth) ( ≈ 28 cm )