This list contains several (but by no means all) non-SI units and their SI equivalents. Many are archaic, but others are still in common usage.

Name | Symbol | Value in SI Units |
---|---|---|

acre (US survey) | ac | 4046.873 m^{2} |

angstrom | Å | 10^{-10} m |

are | a | 1 dam^{2} |

astronomical unit | ua | 1.49598 x 10^{11} m (approx.) |

atmosphere | atm | 1.01325 x 10^{5} Pa |

atomic mass unit | u | 1.66054 x 10^{-27} kg (approx.) |

bar | bar | 10^{5} Pa |

barn | b | 10^{-28} m^{2} |

barrel (drum, 55 US gallons) | bbl | 208.4 L |

calorie (international table) | cal | 4.1868 J |

curie | Ci | 3.7 x 10^{10} Bq |

day | d | 86,400 s |

degree (angle) | ° | (π/180) rad |

dyne | dyn | 10^{-5} N |

electron volt | eV | 1.60218 x 10^{-19} J (approx.) |

erg | erg | 100 nJ |

fathom | fm | 1.8288 m |

footcandle | fc | 10.764 lx |

furlong | fur | 201.168 m |

gallon (US liquid) | gal | 3.785 L |

gauss | Gs | 10^{-4} T |

hectare | ha | 1 hm^{2} |

horsepower | hp | 745.7 W |

hour | h | 3,600 s |

inch | in | 2.54 cm |

light year | ly | 9.46 Pm |

liter | L | 1 dm^{3} |

knot | kt | (1852/3600) m/s = .514 m/s (approx.) |

metric ton (tonne) | t | 10^{3} kg |

minute (angle) | ' | (1/60)° = (π/10,800) rad |

minute (time) | min | 60 s |

nautical mile | nm | 1852 m |

parsec | pc | 30.857 Pm |

rad | rad | 1 cGy |

rem | rem | 1 cSv |

revolutions per minute | rpm | 10.472 mrad/s |

roentgen | R | 2.58 x 10^{-4} C/kg |

second (angle) | " | (1/60)' = (π/648,000) rad |

yard | yd | 91.44 cm |