| imperial barrel | 1 bl (imp) | 2 bl (imp) | 3 bl (imp) | 4 bl (imp) | 5 bl (imp) | 6 bl (imp) | 7 bl (imp) | 8 bl (imp) | 9 bl (imp) | 10 bl (imp) | 11 bl (imp) | 12 bl (imp) | 13 bl (imp) | 14 bl (imp) | 15 bl (imp) | 16 bl (imp) | 17 bl (imp) | 18 bl (imp) | 19 bl (imp) | 20 bl (imp) | 21 bl (imp) | 22 bl (imp) | 23 bl (imp) | 24 bl (imp) | 25 bl (imp) | 26 bl (imp) | 27 bl (imp) | 28 bl (imp) | 29 bl (imp) | 30 bl (imp) | 31 bl (imp) | 32 bl (imp) | 33 bl (imp) | 34 bl (imp) | 35 bl (imp) | 36 bl (imp) | 37 bl (imp) | 38 bl (imp) | 39 bl (imp) | 40 bl (imp) | 41 bl (imp) | 42 bl (imp) | 43 bl (imp) | 44 bl (imp) | 45 bl (imp) | 46 bl (imp) | 47 bl (imp) | 48 bl (imp) | 49 bl (imp) | 50 bl (imp) | 51 bl (imp) | 52 bl (imp) | 53 bl (imp) | 54 bl (imp) | 55 bl (imp) | 56 bl (imp) | 57 bl (imp) | 58 bl (imp) | 59 bl (imp) | 60 bl (imp) | 61 bl (imp) | 62 bl (imp) | 63 bl (imp) | 64 bl (imp) | 65 bl (imp) | 66 bl (imp) | 67 bl (imp) | 68 bl (imp) | 69 bl (imp) | 70 bl (imp) | 71 bl (imp) | 72 bl (imp) | 73 bl (imp) | 74 bl (imp) | 75 bl (imp) | 76 bl (imp) | 77 bl (imp) | 78 bl (imp) | 79 bl (imp) | 80 bl (imp) | 81 bl (imp) | 82 bl (imp) | 83 bl (imp) | 84 bl (imp) | 85 bl (imp) | 86 bl (imp) | 87 bl (imp) | 88 bl (imp) | 89 bl (imp) | 90 bl (imp) | 91 bl (imp) | 92 bl (imp) | 93 bl (imp) | 94 bl (imp) | 95 bl (imp) | 96 bl (imp) | 97 bl (imp) | 98 bl (imp) | 99 bl (imp) | 100 bl (imp) |
| US liquid gallon | 43.2341973 US gal lqd | 86.4683946 US gal lqd | 129.7025920 US gal lqd | 172.9367893 US gal lqd | 216.1709866 US gal lqd | 259.4051839 US gal lqd | 302.6393812 US gal lqd | 345.8735785 US gal lqd | 389.1077759 US gal lqd | 432.3419732 US gal lqd | 475.5761705 US gal lqd | 518.8103678 US gal lqd | 562.0445651 US gal lqd | 605.2787625 US gal lqd | 648.5129598 US gal lqd | 691.7471571 US gal lqd | 734.9813544 US gal lqd | 778.2155517 US gal lqd | 821.4497490 US gal lqd | 864.6839464 US gal lqd | 907.9181437 US gal lqd | 951.1523410 US gal lqd | 994.3865383 US gal lqd | 1,037.6207356 US gal lqd | 1,080.8549330 US gal lqd | 1,124.0891303 US gal lqd | 1,167.3233276 US gal lqd | 1,210.5575249 US gal lqd | 1,253.7917222 US gal lqd | 1,297.0259195 US gal lqd | 1,340.2601169 US gal lqd | 1,383.4943142 US gal lqd | 1,426.7285115 US gal lqd | 1,469.9627088 US gal lqd | 1,513.1969061 US gal lqd | 1,556.4311035 US gal lqd | 1,599.6653008 US gal lqd | 1,642.8994981 US gal lqd | 1,686.1336954 US gal lqd | 1,729.3678927 US gal lqd | 1,772.6020900 US gal lqd | 1,815.8362874 US gal lqd | 1,859.0704847 US gal lqd | 1,902.3046820 US gal lqd | 1,945.5388793 US gal lqd | 1,988.7730766 US gal lqd | 2,032.0072740 US gal lqd | 2,075.2414713 US gal lqd | 2,118.4756686 US gal lqd | 2,161.7098659 US gal lqd | 2,204.9440632 US gal lqd | 2,248.1782605 US gal lqd | 2,291.4124579 US gal lqd | 2,334.6466552 US gal lqd | 2,377.8808525 US gal lqd | 2,421.1150498 US gal lqd | 2,464.3492471 US gal lqd | 2,507.5834445 US gal lqd | 2,550.8176418 US gal lqd | 2,594.0518391 US gal lqd | 2,637.2860364 US gal lqd | 2,680.5202337 US gal lqd | 2,723.7544310 US gal lqd | 2,766.9886284 US gal lqd | 2,810.2228257 US gal lqd | 2,853.4570230 US gal lqd | 2,896.6912203 US gal lqd | 2,939.9254176 US gal lqd | 2,983.1596150 US gal lqd | 3,026.3938123 US gal lqd | 3,069.6280096 US gal lqd | 3,112.8622069 US gal lqd | 3,156.0964042 US gal lqd | 3,199.3306015 US gal lqd | 3,242.5647989 US gal lqd | 3,285.7989962 US gal lqd | 3,329.0331935 US gal lqd | 3,372.2673908 US gal lqd | 3,415.5015881 US gal lqd | 3,458.7357855 US gal lqd | 3,501.9699828 US gal lqd | 3,545.2041801 US gal lqd | 3,588.4383774 US gal lqd | 3,631.6725747 US gal lqd | 3,674.9067720 US gal lqd | 3,718.1409694 US gal lqd | 3,761.3751667 US gal lqd | 3,804.6093640 US gal lqd | 3,847.8435613 US gal lqd | 3,891.0777586 US gal lqd | 3,934.3119560 US gal lqd | 3,977.5461533 US gal lqd | 4,020.7803506 US gal lqd | 4,064.0145479 US gal lqd | 4,107.2487452 US gal lqd | 4,150.4829425 US gal lqd | 4,193.7171399 US gal lqd | 4,236.9513372 US gal lqd | 4,280.1855345 US gal lqd | 4,323.4197318 US gal lqd |
A barrel is one of several units of volume applied in various contexts; there are dry barrels, fluid barrels (such as the UK beer barrel and US beer barrel), oil barrels and so on. For historical reasons the volumes of some barrel units are roughly double the volumes of others; volumes in common usage range from about 100 to 200 litres (22 to 44 imp gal; 26 to 53 US gal). In many connections the term "drum" is used almost interchangeably with "barrel".
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| imperial barrel | bl (imp) | ≡ 36 gal (imp) | = 0.16365924 m3 | Imperial/US |
| imperial barrels | US liquid gallons | imperial barrels | US liquid gallons |
|---|---|---|---|
| 1 | = 43.234197318175 | 6 | = 259.40518390905 |
| 2 | = 86.46839463635 | 7 | = 302.63938122722 |
| 3 | = 129.70259195452 | 8 | = 345.8735785454 |
| 4 | = 172.9367892727 | 9 | = 389.10777586357 |
| 5 | = 216.17098659087 | 10 | = 432.34197318175 |
The US gallon is legally defined as 231 cubic inches, which is exactly 3.785411784 liters. A US liquid gallon of water weighs about 8.34 pounds or 3.78 kilograms at 62 °F (17 °C), making it about 16.6% lighter than the imperial gallon. There are four quarts in a gallon, two pints in a quart and 16 US fluid ounces in a US pint, which makes the US fluid ounce equal to 1⁄128 of a US gallon. In order to overcome the effects of expansion and contraction with temperature when using a gallon to specify a quantity of material for purposes of trade, it is common to define the temperature at which the material will occupy the specified volume. For example, the volume of petroleum products and alcoholic beverages are both referenced to 60 °F (16 °C) in government regulations.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| US liquid gallon | US gal lqd | ≡ 231 cu in | ≡ 3.785411784×10−3 m3 | Imperial/US |
| US liquid gallons | imperial barrels | US liquid gallons | imperial barrels |
|---|---|---|---|
| 1 | = 0.023129838461916 | 6 | = 0.1387790307715 |
| 2 | = 0.046259676923833 | 7 | = 0.16190886923341 |
| 3 | = 0.069389515385749 | 8 | = 0.18503870769533 |
| 4 | = 0.092519353847665 | 9 | = 0.20816854615725 |
| 5 | = 0.11564919230958 | 10 | = 0.23129838461916 |
| imperial barrels | US liquid gallons |
|---|---|
| 1 | = 43.2341973 |
| 0.0231298 | = 1 |
| Symbol | Definition |
|---|---|
| ≡ | exactly equal |
| ≈ | approximately equal to |
| = | equal to |
| digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |