21 inches

TV & monitor size

18.3 x 10.3 in

Aspect ratio 4:3

Aspect ratio 5:4

Aspect ratio 16:9

Aspect ratio 16:10

Aspect ratio 21:9

Aspect ratio 32:9

Metric

  • Kilometre (km)
    4.65×10⁻⁴ x 2.62×10⁻⁴
  • Metre (m)
    0.46 x 0.26
  • Decimetre (dm)
    4.65 x 2.62
  • Centimetre (cm)
    46.49 x 26.15
  • Millimetre (mm)
    464.9 x 261.51
  • Micrometre (µm)
    464,898.39 x 261,505.35
  • Nanometre (nm)
    464,898,391.5 x 261,505,345.22
  • Angstrom (Å)
    4.65×10⁹ x 2.62×10⁹

British/American

  • League
    9.63×10⁻⁵ x 5.42×10⁻⁵
  • Mile (mi)
    2.89×10⁻⁴ x 1.62×10⁻⁴
  • Furlong
    2.31×10⁻³ x 1.3×10⁻³
  • Chain
    0.02 x 0.01
  • Rod (rd)
    0.09 x 0.05
  • Yard (yd)
    0.51 x 0.29
  • Foot (ft)
    1.53 x 0.86
  • Link
    2.31 x 1.3
  • Hand
    4.58 x 2.57
  • Inch (in)
    18.3 x 10.3
  • Line
    183.03 x 102.95
  • Mil (mil)
    18,303.09 x 10,295.49
  • Thou (thou)
    18,303.09 x 10,295.49

Nautical

  • Nautical mile
    2.51×10⁻⁴ x 1.41×10⁻⁴
  • Fathom
    0.25 x 0.14

Astronomical

  • Parsec (pc)
    1.51×10⁻¹⁷ x 8.47×10⁻¹⁸
  • Light year
    4.91×10⁻¹⁷ x 2.76×10⁻¹⁷
  • Astronomical unit (AE)
    3.11×10⁻¹² x 1.75×10⁻¹²
  • Light minute
    2.58×10⁻¹¹ x 1.45×10⁻¹¹
  • Light second
    1.55×10⁻⁹ x 8.72×10⁻¹⁰