Length Length | Name of unit | Symbol | Definition | Relation to SI units | angstrom | Å | ≡ 1×10−10 m | ≡ 0.1 nm | astronomical unit | AU | ≈ Distance from Earth to Sun | ≈ 149597871464 m [1] | barleycorn (H) | | = ⅓ in (see note above about rounding) | ≈ 8.46×10−3 m | bohr, atomic unit of length | a0 | ≡ Bohr radius of hydrogen | ≈ 5.2917720859×10−11 ± 3.6×10−20 m[2] | cable length (imperial) | | ≡ 608 ft | ≈ 185.3184 m | cable length (International) | | ≡ 1/10 nmi | ≡ 185.2 m | cable length (US) | | ≡ 720 ft | = 219.456 m | chain (Gunter's; Surveyor's) | ch | ≡ 66 ft(US) ≡ 4 rods [3] | ≈ 20.11684 m | cubit (H) | | ≡ Distance from fingers to elbow ≈ 18 in | ≈ 0.5 m | ell (H) | ell | ≡ 45 in [4] (In England usually) | = 1.143 m | fathom | fm | ≡ 6 ft [4] | = 1.8288 m | fermi | fm | ≡ 1×10−15 m[4] | ≡ 1×10−15 m | finger | | ≡ 7/8 in | = 0.022225 m | finger (cloth) | | ≡ 4½ in | = 0.1143 m | foot (Benoît) (H) | ft (Ben) | | ≈ 0.304799735 m | foot (Cape) (H) | | Legally defined as 1.033 English feet in 1859 | ≈ 0.314858 m | foot (Clarke's) (H) | ft (Cla) | | ≈ 0.3047972654 m | foot (Indian) (H) | ft Ind | | ≈ 0.304799514 m | foot (International) | ft | ≡ 1/3 yd ≡ 0.3048 m ≡ 12 inches | ≡ 0.3048 m | foot (Sear's) (H) | ft (Sear) | | ≈ 0.30479947 m | foot (US Survey) | ft (US) | ≡ 1200⁄3937 m [5] | ≈ 0.304800610 m | french; charriere | F | ≡ 1⁄3 mm | = 0.3 ×10−3 m | furlong | fur | ≡ 10 chains = 660 ft = 220 yd [4] | = 201.168 m | hand | | ≡ 4 in [4] | ≡ 0.1016 m | inch (International) | in | ≡ 1/36 yd ≡ 1/12 ft | ≡ 0.0254 m | league (land) | lea | ≡ 3 US Statute miles [3] | = 4828.032 m | light-day | | ≡ 24 light-hours | ≡ 2.59020683712×1013 m | light-hour | | ≡ 60 light-minutes | ≡ 1.0792528488×1012 m | light-minute | | ≡ 60 light-seconds | ≡ 1.798754748×1010 m | light-second | | ≡ Distance light travels in one second in vacuum | ≡ 299792458 m | light-year | ly | ≡ Distance light travels in vacuum in 365.25 days [6] | = 9.4607304725808×1015 m | line | ln | ≡ 1/12 in [7] | = 0.002116 m | link (Gunter's; Surveyor's) | lnk | ≡ 1/100 ch [4] ≡ 0.66 ft ≡ 7.92in | = 0.201168 m | link (Ramsden's; Engineer's) | lnk | ≡ 1 ft [4] | = 0.3048 m | metre (SI base unit) | m | ≡ Distance light travels in 1⁄299792458 of a second in vacuum.[8]
≈ 1⁄10000000 of the distance from equator to pole. | ≡ 1 m | mickey | | ≡ 1⁄200 in | = 1.27×10−4 m | micron | µ | | ≡ 1×10−6 m | mil; thou | mil | ≡ 1×10−3 in | ≡ 2.54×10−5 m | mil (Sweden and Norway) | mil | ≡ 10 km | = 10000 m | mile (geographical) (H) | | ≡ 6082 ft | = 1853.7936 m | mile (international) | mi | ≡ 80 chains ≡ 5280 ft ≡ 1760 yd | ≡ 1609.344 m | mile (tactical or data) | | ≡ 6000 ft | ≡ 1828.8 m | mile (telegraph) (H) | mi | ≡ 6087 ft | = 1855.3176 m | mile (US Survey) | mi | ≡ 5280 US Survey feet ≡ (5280 × 1200⁄3937) m | ≈ 1609.347219 m | nail (cloth) | | ≡ 2¼ in [4] | = 0.057 15 m | nanometer | nm | ≡ 1×10−9 m | ≡ 1×10−9 m | nautical league | NL; nl | ≡ 3 nmi [4] | = 5556 m | nautical mile (Admiralty) | NM (Adm); nmi (Adm) | = 6080 ft | = 1853.184 m | nautical mile (international) | NM; nmi | ≡ 1852 m [9] | ≡ 1852 m | nautical mile (US pre 1954) | | ≡ 1853.248 m | ≡ 1853.248 m | pace | | ≡ 2.5 ft [4] | = 0.762 m | palm | | ≡ 3 in [4] | = 0.0762 m | parsec | pc | Distance of star with parallax shift of one arc second from a base of one astronomical unit | ≈ 3.085 677 82×1016 ± 6×106 m [10] | pica | | ≡ 12 points | Dependent on point measures. | point (American, English)[11][12] | pt | ≡ 1/72.272 in | ≈ 0.000 351 450 m | point (Didot; European) [12][13] | pt | ≡ 1/12 × 1/72 of pied du roi;

After 1878:
≡ 5/133 cm | ≈ 0.000 375 97 m;

After 1878:
≈ 0.000 375 939 85 m | point (PostScript) [11] | pt | ≡ 1/72 in | = 0.000 352 7 m | point (TeX) [11] | pt | ≡ 1/72.27 in | = 0.000 351 4598 m | quarter | | ≡ ¼ yd | = 0.2286 m | rod; pole; perch (H) | rd | ≡ 16½ ft | = 5.0292 m | rope (H) | rope | ≡ 20 ft [4] | = 6.096 m | span (H) | | ≡ 9 in [4] | = 0.2286 m | spat [14] | | | ≡ 1×1012 m | stick (H) | | ≡ 2 in | = 0.0508 m | stigma; bicron (picometre) | pm | | ≡ 1×10−12 m | twip | twp | ≡ 1/1440 in | = 1.7638×10−5 m | x unit; siegbahn | xu | | ≈ 1.0021×10−13 m [4] | yard (International) | yd | ≡ 0.9144 m [5] ≡ 3 ft ≡ 36 in | ≡ 0.9144 m |
Area
Area | Name of unit | Symbol | Definition | Relation to SI units | acre (international) | ac | ≡ 1 ch × 10 ch = 4840 sq yd | ≡ 4 046.856 4224 m2 | acre (U. S. survey) | ac | ≡ 10 sq ch = 4840 sq yd, also 43560 sq ft. | ≈ 4 046.873 m2 [15] | are | a | ≡ 100 m2 | = 100 m2 | barn | b | ≡ 10−28 m2 | = 10−28 m2 | barony | | ≡ 4000 ac | ≈ 1.618 742×107 m2 | board | bd | ≡ 1 in × 1 ft | = 7.741 92×10−3 m2 | boiler horsepower equivalent direct radiation | bhp EDR | ≡ (1 ft2) (1 bhp) / (240 BTUIT/h) | ≈ 12.958 174 m2 | circular inch | circ in | ≡ π/4 sq in | ≈ 5.067 075×10−4 m2 | circular mil; circular thou | circ mil | ≡ π/4 mil2 | ≈ 5.067 075×10−10 m2 | cord | | ≡ 192 bd | = 1.486 448 64 m2 | dunam | | ≡ 1 000 m2 | = 1 000 m2 | guntha | | ≡ 121 sq yd | ≈ 101.17 m2 | hectare | ha | ≡ 10 000 m2 | ≡ 10 000 m2 | hide | | ≈ 120 ac (variable) | ≈ 5×105 m2 | rood | ro | ≡ ¼ ac | = 1 011.714 1056 m2 | section | | ≡ 1 mi × 1 mi | = 2.589 988 110 336×106 m2 | shed | | ≡ 10−52 m2 | = 10−52 m2 | square (roofing) | | ≡ 10 ft × 10 ft | = 9.290 304 m2 | square chain (international) | sq ch | ≡ 66 ft × 66 ft = 1/10 ac | ≡ 404.685 642 24 m2 | square chain (US Survey) | sq ch | ≡ 66 ft(US) × 66 ft(US) = 1/10 ac | ≈ 404.687 3 m2 | square foot | sq ft | ≡ 1 ft × 1 ft | ≡ 9.290 304×10−2 m2 | square foot (US Survey) | sq ft | ≡ 1 ft (US) × 1 ft (US) | ≈ 9.290 341 161 327 49×10−2m2 | square inch | sq in | ≡ 1 in × 1 in | ≡ 6.4516×10−4 m2 | square kilometre | km2 | ≡ 1 km × 1 km | = 106 m2 | square link (Gunter's)(International) | sq lnk | ≡ 1 lnk × 1 lnk ≡ 0.66 ft × 0.66 ft | = 4.046 856 4224×10−2 m2 | square link (Gunter's)(US Survey) | sq lnk | ≡ 1 lnk × 1 lnk ≡ 0.66 ft(US) × 0.66 ft(US) | ≈ 4.046 872×10−2 m2 | square link (Ramsden's) | sq lnk | ≡ 1 lnk × 1 lnk ≡ 1 ft × 1 ft | = 0.09290304 m2 | square metre (SI unit) | m2 | ≡ 1 m × 1 m | = 1 m2 | square mil; square thou | sq mil | ≡ 1 mil × 1 mil | = 6.4516×10−10 m2 | square mile | sq mi | ≡ 1 mi × 1 mi | = 2.589 988 110 336×106 m2 | square mile (US Survey) | sq mi | ≡ 1 mi (US) × 1 mi (US) | ≈ 2.589 998 47×106 m2 | square rod/pole/perch | sq rd | ≡ 1 rd × 1 rd | = 25.292 852 64 m2 | square yard (International) | sq yd | ≡ 1 yd × 1 yd | ≡ 0.836 127 36 m2 | stremma | | ≡ 1 000 m2 | = 1 000 m2 | township | | ≡ 36 sq mi (US) | ≈ 9.323 994×107 m2 | yardland | | ≈ 30 ac | ≈ 1.2×105 m2 |

Volume Volume | Name of unit | Symbol | Definition | Relation to SI units | acre-foot | ac ft | ≡ 1 ac x 1 ft = 43 560 ft3 | = 1 233.481 837 547 52 m3 | acre-inch | | ≡ 1 ac × 1 in | = 102.790 153 128 96 m3 | barrel (imperial) | bl (imp) | ≡ 36 gal (imp) | = 0.163 659 24 m3 | barrel (petroleum) | bl; bbl | ≡ 42 gal (US) | = 0.158 987 294 928 m3 | barrel (US dry) | bl (US) | ≡ 105 qt (US) = 105/32 bu (US lvl) | = 0.115 628 198 985 075 m3 | barrel (US fluid) | fl bl (US) | ≡ 31½ gal (US) | = 0.119 240 471 196 m3 | board-foot | fbm | ≡ 144 cu in | ≡ 2.359 737 216×10−3 m3 | bucket (imperial) | bkt | ≡ 4 gal (imp) | = 0.018 184 36 m3 | bushel (imperial) | bu (imp) | ≡ 8 gal (imp) | = 0.036 368 72 m3 | bushel (US dry heaped) | bu (US) | ≡ 1 ¼ bu (US lvl) | = 0.044 048 837 7086 m3 | bushel (US dry level) | bu (US lvl) | ≡ 2 150.42 cu in | = 0.035 239 070 166 88 m3 | butt, pipe | | ≡ 126 gal (wine) | = 0.476 961 884 784 m3 | coomb | | ≡ 4 bu (imp) | = 0.145 474 88 m3 | cord (firewood) | | ≡ 8 ft × 4 ft × 4 ft | = 3.624 556 363 776 m3 | cord-foot | | ≡ 16 cu ft | = 0.453 069 545 472 m3 | cubic fathom | cu fm | ≡ 1 fm × 1 fm × 1 fm | = 6.116 438 863 872 m3 | cubic foot | cu ft | ≡ 1 ft × 1 ft × 1 ft | ≡ 0.028 316 846 592 m3 | cubic inch | cu in | ≡ 1 in × 1 in × 1 in | ≡ 16.387 064×10−6 m3 | cubic metre (SI unit) | m3 | ≡ 1 m × 1 m × 1 m | ≡ 1 m3 | cubic mile | cu mi | ≡ 1 mi × 1 mi × 1 mi | ≡ 4 168 181 825.440 579 584 m3 | cubic yard | cu yd | ≡ 27 cu ft | ≡ 0.764 554 857 984 m3 | cup (breakfast) | | ≡ 10 fl oz (imp) | = 284.130 625×10−6 m3 | cup (Canadian) | c (CA) | ≡ 8 fl oz (imp) | = 227.3045×10−6 m3 | cup (metric) | c | ≡ 250.0×10−6 m3 | = 250.0×10−6 m3 | cup (US customary) | c (US) | ≡ 8 US fl oz ≡ 1/16 gal (US) | = 236.588 2365×10−6 m3 | cup (US food nutrition labeling) | c (US) | ≡ 240 mL[16] | = 2.4×10−4 m3 | dash (imperial) | | ≡ 1/384 gi (imp) = ½ pinch (imp) | = 369.961 751 302 08 3×10−9 m3 | dash (US) | | ≡ 1/96 US fl oz = ½ US pinch | = 308.057 599 609 375×10−9 m3 | dessertspoon (imperial) | | ≡ 1/12 gi (imp) | = 11.838 776 0416×10−6 m3 | drop (imperial) | gtt | ≡ 1/288 fl oz (imp) | = 98.656 467 013 8×10−9 m3 | drop (imperial) (alt) | gtt | ≡ 1/1 824 gi (imp) | ≈ 77.886 684×10−9 m3 | drop (medical) | | ≡ 0.9964/12 ml | = 83.03×10−9 m3 | drop (medical) | | ≡ 1/12 ml | = 83.3×10−9 m3 | drop (metric) | | ≡ 1/20 mL | = 50.0×10−9 m3 | drop (US) | gtt | ≡ 1/360 US fl oz | = 82.148 693 22916×10−9 m3 | drop (US) (alt) | gtt | ≡ 1/456 US fl oz | ≈ 64.854 231 496 71×10−9 m3 | drop (US) (alt) | gtt | ≡ 1/576 US fl oz | ≈ 51.342 933 268 23×10−9 m3 | fifth | | ≡ 1/5 US gal | = 757.082 3568×10−6 m3 | firkin | | ≡ 9 gal (US) | = 0.034 068 706 056 m3 | fluid drachm (imperial) | fl dr | ≡ ⅛ fl oz (imp) | = 3.551 632 8125×10−6 m3 | fluid dram (US); US fluidram | fl dr | ≡ ⅛ US fl oz | = 3.696 691 195 3125×10−6 m3 | fluid scruple (imperial) | fl s | ≡ 1/24 fl oz (imp) | = 1.183 877 60416×10−6 m3 | gallon (beer) | beer gal | ≡ 282 cu in | = 4.621 152 048×10−3 m3 | gallon (imperial) | gal (imp) | ≡ 4.546 09 L | ≡ 4.546 09×10−3 m3 | gallon (US dry) | gal (US) | ≡ ⅛ bu (US lvl) | = 4.404 883 770 86×10−3 m3 | gallon (US fluid; Wine) | gal (US) | ≡ 231 cu in | ≡ 3.785 411 784×10−3 m3 | gill (imperial); Noggin | gi (imp); nog | ≡ 5 fl oz (imp) | = 142.065 3125×10−6 m3 | gill (US) | gi (US) | ≡ 4 US fl oz | = 118.294 118 25×10−6 m3 | hogshead (imperial) | hhd (imp) | ≡ 2 bl (imp) | = 0.327 318 48 m3 | hogshead (US) | hhd (US) | ≡ 2 fl bl (US) | = 0.238 480 942 392 m3 | jigger (bartending) | | ≡ 1½ US fl oz | ≈ 44.36×10−6 m3 | kilderkin | | ≡ 18 gal (imp) | = 0.081 829 62 m3 | lambda | λ | ≡ 1 mm3 | = 1×10−9 m3 | last | | ≡ 80 bu (imp) | = 2.909 4976 m3 | litre | L | ≡ 1 dm3 [17] | ≡ 0.001 m3 | load | | ≡ 50 cu ft | = 1.415 842 3296 m3 | minim (imperial) | min | ≡ 1/480 fl oz (imp) = 1/60 fl dr (imp) | = 59.193 880 208 3×10−9 m3 | minim (US) | min | ≡ 1/480 US fl oz = 1/60 US fl dr | = 61.611 519 921 875×10−9 m3 | ounce (fluid imperial) | fl oz (imp) | ≡ 1/160 gal (imp) | ≡ 28.413 0625×10−6 m3 | ounce (fluid US customary) | US fl oz | ≡ 1/128 gal (US) | ≡ 29.573 529 5625×10−6 m3 | ounce (fluid US food nutrition labeling) | US fl oz | ≡ 30 mL[16] | ≡ 3×10−5 m3 | peck (imperial) | pk | ≡ 2 gal (imp) | = 9.092 18×10−3 m3 | peck (US dry) | pk | ≡ ¼ US lvl bu | = 8.809 767 541 72×10−3 m3 | perch | per | ≡ 16½ ft × 1½ ft × 1 ft | = 0.700 841 953 152 m3 | pinch (imperial) | | ≡ 1/192 gi (imp) = ⅛ tsp (imp) | = 739.923 502 60416×10−9 m3 | pinch (US) | | ≡ 1/48 US fl oz = ⅛ US tsp | = 616.115 199 218 75×10−9 m3 | pint (imperial) | pt (imp) | ≡ ⅛ gal (imp) | = 568.261 25×10−6 m3 | pint (US dry) | pt (US dry) | ≡ 1/64 bu (US lvl) ≡ ⅛ gal (US dry) | = 550.610 471 3575×10−6 m3 | pint (US fluid) | pt (US fl) | ≡ ⅛ gal (US) | = 473.176 473×10−6 m3 | pony | | ≡ 3/4 US fl oz | = 22.180 147 171 875×10−6 m3 | pottle; quartern | | ≡ ½ gal (imp) = 80 fl oz (imp) | = 2.273 045×10−3 m3 | quart (imperial) | qt (imp) | ≡ ¼ gal (imp) | = 1.136 5225×10−3 m3 | quart (US dry) | qt (US) | ≡ 1/32 bu (US lvl) = ¼ gal (US dry) | = 1.101 220 942 715×10−3 m3 | quart (US fluid) | qt (US) | ≡ ¼ gal (US fl) | = 946.352 946×10−6 m3 | quarter; pail | | ≡ 8 bu (imp) | = 0.290 949 76 m3 | register ton | | ≡ 100 cu ft | = 2.831 684 6592 m3 | sack (imperial); bag | | ≡ 3 bu (imp) | = 0.109 106 16 m3[citation needed] | sack (US) | | ≡ 3 bu (US lvl) | = 0.105 717 210 500 64 m3 | seam | | ≡ 8 bu (US lvl) | = 0.281 912 561 335 04m3[citation needed] | shot | | ≡ 1 US fl oz | ≈ 29.57×10−6 m3 | strike (imperial) | | ≡ 2 bu (imp) | = 0.072 737 44 m3 | strike (US) | | ≡ 2 bu (US lvl) | = 0.070 478 140 333 76 m3 | tablespoon (Australian metric) | | | ≡ 20.0×10−6 m3 | tablespoon (Canadian) | tbsp | ≡ ½ fl oz (imp) | = 14.206 531 25×10−6 m3 | tablespoon (imperial) | tbsp | ≡ 5/8 fl oz (imp) | = 17.758 164 0625×10−6 m3 | tablespoon (metric) | | | ≡ 15.0×10−6 m3 | tablespoon (US customary) | tbsp | ≡ ½ US fl oz | = 14.786 764 7825×10−6 m3 | tablespoon (US food nutrition labeling) | tbsp | ≡ 15 mL[16] | = 1.5×10−5 m3 | teaspoon (Canadian) | tsp | ≡ 1/6 fl oz (imp) | = 4.735 510 416×10−6 m3 | teaspoon (imperial) | tsp | ≡ 1/24 gi (imp) | = 5.919 388 02083×10−6 m3 | teaspoon (metric) | | ≡ 5.0×10−6 m3 | = 5.0×10−6 m3 | teaspoon (US customary) | tsp | ≡ 1/6 US fl oz | = 4.928 921 595×10−6 m3 | teaspoon (US food nutrition labeling) | tsp | ≡ 5 mL[16] | = 5×10−6 m3 | timber foot | | ≡ 1 cu ft | = 0.028 316 846 592 m3 | ton (displacement) | | ≡ 35 cu ft | = 0.991 089 630 72 m3 | ton (freight) | | ≡ 40 cu ft | = 1.132 673 863 68 m3 | ton (water) | | ≡ 28 bu (imp) | = 1.018 324 16 m3 | tun | | ≡ 252 gal (wine) | = 0.953 923 769 568 m3 | wey (US) | | ≡ 40 bu (US lvl) | = 1.409 562 806 6752 m3 |

Density Density | Name of unit | Symbol | Definition | Relation to SI units | gram per millilitre | g/mL | ≡ g/mL | = 1,000 kg/m3 | kilogram per cubic metre (SI unit) | kg/m3 | ≡ kg/m3 | = 1 kg/m3 | kilogram per litre | kg/L | ≡ kg/L | = 1,000 kg/m3 | ounce (avoirdupois) per cubic foot | oz/ft3 | ≡ oz/ft3 | ≈ 1.001153961 kg/m3 | ounce (avoirdupois) per cubic inch | oz/in3 | ≡ oz/in3 | ≈1.729994044×103 kg/m3 | ounce (avoirdupois) per gallon (imperial) | oz/gal | ≡ oz/gal | ≈ 6.236023291 kg/m3 | ounce (avoirdupois) per gallon (US fluid) | oz/gal | ≡ oz/gal | ≈ 7.489151707 kg/m3 | pound (avoirdupois) per cubic foot | lb/ft3 | ≡ lb/ft3 | ≈ 16.01846337 kg/m3 | pound (avoirdupois) per cubic inch | lb/in3 | ≡ lb/in3 | ≈2.767990471×104 kg/m3 | pound (avoirdupois) per gallon (imperial) | lb/gal | ≡ lb/gal | ≈ 99.77637266 kg/m3 | pound (avoirdupois) per gallon (US fluid) | lb/gal | ≡ lb/gal | ≈ 119.8264273 kg/m3 | slug per cubic foot | slug/ft3 | ≡ slug/ft3 | ≈ 515.3788184 kg/m3 |