| Name | symbol | equivalence(s) in smaller units | equivalence(s) in larger units | standard equivalent | hint |
|---|---|---|---|---|---|
| quectometre or quectometer | qm | 0.001 rm | 10⁻³⁰ m one nonillionth of a metre | ||
| rontometre or rontometer | rm | 1,000 qm | 0.001 ym | 10⁻²⁷ m one octillionth of a metre | |
| yoctometre or yoctometer | ym | 1,000 rm | 0.001 zm | 10⁻²⁴ m one septillionth of a metre | |
| zeptometre or zeptometer | zm | 1,000 ym | 0.001 am | 10⁻²¹ m one sextillionth of a metre | |
| attometre or attometer | am | 1,000 zm | 0.001 fm | 10⁻¹⁸ m one quintillionth of a metre | |
| femtometre or femtometer | fm | 1,000 am | 0.001 pm | 10⁻¹⁵ m one quadrillionth of a metre | |
| picometre or picometer | pm | 1,000 fm | 0.001 nm | 10⁻¹² m one trillionth of a metre | |
| nanometre or nanometer | nm | 1,000 pm | 0.001 µm | 10⁻⁹ m one billionth of a metre | |
| micrometre or micron | µm | 1,000 nm | 0.001 mm | 10⁻⁶ m one millionth of a metre | |
| mil | 25.4 µm | ¹⁄₁₀₀₀ inch | 25.4 µm | ||
| point | pt. | about 353 µm | ¹⁄₇₂ inch | 352.7̅7 µm | typography |
| millimetre or millimeter | mm | 1,000 µm | 0.1 cm about 0.3937 inch | 0.001 m = 10⁻³ m one thousandth of a metre | |
| line | 6 points | ¹⁄₁₂ inch | 2.116̅6 mm | typography | |
| barleycorn | ⅓ inch | 8.46̅6 mm | |||
| centimetre or centimeter | cm | 10 mm | 0.1 dm | 0.01 m = 10⁻² m one hundredth of a metre | |
| inch | in. or ″ | 72 points 3 barleycorns 2.54 cm | ¼ hand ¹⁄₁₂ foot ¹∕₃₆ yard | 25.4 mm 2.54 cm 0.0254 m | |
| decimetre or decimeter | dm | 10 cm | 0.1 m | 0.1 m = 10⁻¹ m one tenth of a metre | |
| hand | 4 inches | ⅓ foot | 10.16 cm | equestrian | |
| link | 7.92 inches | ¹⁄₂₅ rod ¹⁄₁₀₀ chain | 20.1168 cm | ||
| foot | ft. or ′ | 12 inches | ⅓ yard | 30.48 cm | |
| cubit | about 18 inches or 1½ feet | about ½ yard | about 46 cm | ||
| vara | 33 inches | 83.82 cm | U.S. BLM | ||
| Texan vara | 33⅓ inches | 84.6̅6cm | Texas surveying | ||
| yard | yd. | 36 inches | 3 feet | 91.44 cm | |
| metre or meter | m | 1,000 mm 100 cm 10 dm | 0.1 dam 0.01 hm 0.001 km | base unit | |
| fathom | 6 feet | 1.8288 m | water depth | ||
| rod or pole | 25 links 16½ feet 198 inches | ¼ chain ¹⁄₃₂₀ mile | 5.092 m | land surveying | |
| decametre or dekameter | dam | 10 m | 0.01 km 0.1 hm | 10 m ten metres | rare |
| chain | 4 rods 66 feet 100 links | ¹⁄₈₀ mile | 20.12 m | land surveying | |
| hectometre or hectometer | hm | 100 m | 0.1 km | 100 m one hundred metres | rare |
| furlong | 660 feet 10 chains | ⅛ mile | 201.168 m | ||
| kilometre or kilometer | km | 1,000 m | 0.001 Mm | 1,000 m one thousand metres | |
| mile | mi. | 5,280 feet 1,760 yards | 1.5325344 km | 1,532.5344 m | |
| nautical mile | n.mi. | 6,080.2 feet | 1.852 km | ||
| league | 3 miles or 3 nautical miles or other things | 4.597 to 5.556 km or other length | |||
| myriametre | 10,000 m 10 km | 0.01 Mm | 10,000 m ten thousand metres | rare | |
| megametre or megameter | Mm | 1,000 km | 0.001 Gm | 10⁶ m one million metres | |
| light second | about 300 Mm | 299,792,458 m | |||
| gigametre or gigameter | Gm | 1,000 Mm | 0.001 Tm | 10⁹ m one billion metres | |
| astronomical unit | au | about 150 Gm | 149.5978707 Gm | astronomy | |
| terametre or terameter | Tm | 1,000 Gm | 0.001 Pm | 10¹² m one trillion metres | |
| petametre or petameter | Pm | 1,000 Tm | 0.001 Em | 10¹⁵ m one quadrillion metres | |
| light year | ly | about 9.46 Pm | 9.4607304725808 Pm | astronomy | |
| parsec | pc | 3.26156 ly 206,265 au | 30.857 Pm | astronomy | |
| exametre or exameter | Em | 1,000 Pm | 0.001 Zm | 10¹⁸ m one quintillion metres | |
| zettametre or zettameter | Zm | 1,000 Em | 0.001 Ym | 10²¹ m one sextillion metres | |
| yottametre or yottameter | Ym | 1,000 Zm | 0.001 Rm | 10²⁴ m one septillion metres | |
| ronnametre or ronnameter | Rm | 1,000 Ym | 0.001 Qm | 10²⁷ m one octillion metres | |
| quettametre or quettameter | Qm | 1,000 Rm | 10³⁰ m one nonillion metres |