Units

To measure is to know —Kelvin
physical extension 1D length meter cm mm µm nm pm Å fm am km AU light-year parsec megaparsec inch" foot'(12") yard(3') fathom(6') rod(5½yd) chain furlong(1/8mi) mile nm(6000') league(3mi)
2D area length_unit2 hectare barn acre section township
3D volume length_unit3 cc liter/litre dram tsp Tbsp jig gill shot cup pint quart gallon peck bushel barrel hogshead cord acre-foot
energy electronvolt erg joule (GJ) calorie Calorie kWh megaton BTU
power Watt (kW MW GW TW mW) horsepower hp
mass/weight gram (mg µg ng pg) carat kg tonne grain dram pennyweight ounce (oz) pound (lb) stone firkin hundredweight ton, long ton
information bit b, byte B
time jiffy second (ms µs ns) minute hour day week fortnight month quarter year decade century millenium aeon
angle degree° (arc)minute' (arc)second" radian
temperature °C °F Kelvin
monetary $ ¢ ¥ € £
military fireteam | squad crew section patrol | platoon flight chalk | company battery troop | battalion squadron | regiment brigade group wing | division legion | corps army fleet | army-group
Misc. proof credit

approximation difference percentage
mile
1.6 km -9.344m -.58%
1.61 km +.656m +.04076%
1.609 km -.344m -.02138%
1.609344 km 0 0%

acre = furlong × chain 40 rods × 4 rods 220 yd × 66 ft 4,840 yd2 43,560 ft2 mile2/640 ≈(69.57yd)2 ≈.40468 hectare
section=mile2=640 acres
township=6mi*6mi=36 sections

metre = ≈39.370" ≈3.281' (3' 3.37") ≈1.0936 yd (1yd 3.37")

1 gallon = 231 inches3. Water weighs 8.3454 lbs = 3.785411784 kg. (pint≈lb) (Liter=kg)
Human body volume≈kg/4 Gal
1 fluid ounce = 1/128 gallon = 1.8046875 inches3 = 29.5735295625 ml
1 pound = 0.45359237 kg
grain=67.79891mg     pennyweight=24 grains     dram=27.34 grains≈1.77g     oz=16 drams     lb=16 oz.    
stone=14 lbs     firkin=90lb     cwt hundredweight=8 stone
[long]ton=20 hundredweight=2240 lbs     [short]ton=2000 lbs     tonne=1000kg=2204.6 lbs

inches feet yards fathoms rods chains furlongs miles nautical
miles
foot (ft ') 12
yard (yd) 36 3
fathom 72 6 2
rod 198 16½ 2.75
chain 792 66 22 11 4
furlong 7920 660 220 110 40 10
mile (mi) 63,360 5,280 1,760 880 320 80 8
nautical mile (nm) 72,000 6000 2000 1000 363.6363 90.9090 9.0909 1 3/22 =1.13636
league 3

Joule=107 ergs     Calorie≈4200J
Watt=1J/s     4200W≈1Cal/s    
an average BMR of 1500 Cal/day≈1Cal/min≈70W     one year: 550,000 Cal ≈ 600 kWh
fat: 9Cal/gm=4082Cal/lb