| firkin | 1 firkin | 2 firkin | 3 firkin | 4 firkin | 5 firkin | 6 firkin | 7 firkin | 8 firkin | 9 firkin | 10 firkin | 11 firkin | 12 firkin | 13 firkin | 14 firkin | 15 firkin | 16 firkin | 17 firkin | 18 firkin | 19 firkin | 20 firkin | 21 firkin | 22 firkin | 23 firkin | 24 firkin | 25 firkin | 26 firkin | 27 firkin | 28 firkin | 29 firkin | 30 firkin | 31 firkin | 32 firkin | 33 firkin | 34 firkin | 35 firkin | 36 firkin | 37 firkin | 38 firkin | 39 firkin | 40 firkin | 41 firkin | 42 firkin | 43 firkin | 44 firkin | 45 firkin | 46 firkin | 47 firkin | 48 firkin | 49 firkin | 50 firkin | 51 firkin | 52 firkin | 53 firkin | 54 firkin | 55 firkin | 56 firkin | 57 firkin | 58 firkin | 59 firkin | 60 firkin | 61 firkin | 62 firkin | 63 firkin | 64 firkin | 65 firkin | 66 firkin | 67 firkin | 68 firkin | 69 firkin | 70 firkin | 71 firkin | 72 firkin | 73 firkin | 74 firkin | 75 firkin | 76 firkin | 77 firkin | 78 firkin | 79 firkin | 80 firkin | 81 firkin | 82 firkin | 83 firkin | 84 firkin | 85 firkin | 86 firkin | 87 firkin | 88 firkin | 89 firkin | 90 firkin | 91 firkin | 92 firkin | 93 firkin | 94 firkin | 95 firkin | 96 firkin | 97 firkin | 98 firkin | 99 firkin | 100 firkin |
| US legal cup | 170.478375 c (US Legal) | 340.95675 c (US Legal) | 511.435125 c (US Legal) | 681.9135 c (US Legal) | 852.391875 c (US Legal) | 1,022.87025 c (US Legal) | 1,193.348625 c (US Legal) | 1,363.827 c (US Legal) | 1,534.305375 c (US Legal) | 1,704.78375 c (US Legal) | 1,875.262125 c (US Legal) | 2,045.7405 c (US Legal) | 2,216.218875 c (US Legal) | 2,386.69725 c (US Legal) | 2,557.175625 c (US Legal) | 2,727.654 c (US Legal) | 2,898.132375 c (US Legal) | 3,068.61075 c (US Legal) | 3,239.089125 c (US Legal) | 3,409.5675 c (US Legal) | 3,580.045875 c (US Legal) | 3,750.52425 c (US Legal) | 3,921.002625 c (US Legal) | 4,091.481 c (US Legal) | 4,261.959375 c (US Legal) | 4,432.43775 c (US Legal) | 4,602.916125 c (US Legal) | 4,773.3945 c (US Legal) | 4,943.872875 c (US Legal) | 5,114.35125 c (US Legal) | 5,284.829625 c (US Legal) | 5,455.308 c (US Legal) | 5,625.786375 c (US Legal) | 5,796.26475 c (US Legal) | 5,966.743125 c (US Legal) | 6,137.2215 c (US Legal) | 6,307.699875 c (US Legal) | 6,478.17825 c (US Legal) | 6,648.656625 c (US Legal) | 6,819.135 c (US Legal) | 6,989.613375 c (US Legal) | 7,160.09175 c (US Legal) | 7,330.570125 c (US Legal) | 7,501.0485 c (US Legal) | 7,671.526875 c (US Legal) | 7,842.00525 c (US Legal) | 8,012.483625 c (US Legal) | 8,182.962 c (US Legal) | 8,353.440375 c (US Legal) | 8,523.91875 c (US Legal) | 8,694.397125 c (US Legal) | 8,864.8755 c (US Legal) | 9,035.353875 c (US Legal) | 9,205.83225 c (US Legal) | 9,376.310625 c (US Legal) | 9,546.789 c (US Legal) | 9,717.267375 c (US Legal) | 9,887.74575 c (US Legal) | 10,058.224125 c (US Legal) | 10,228.7025 c (US Legal) | 10,399.180875 c (US Legal) | 10,569.65925 c (US Legal) | 10,740.137625 c (US Legal) | 10,910.616 c (US Legal) | 11,081.094375 c (US Legal) | 11,251.57275 c (US Legal) | 11,422.051125 c (US Legal) | 11,592.5295 c (US Legal) | 11,763.007875 c (US Legal) | 11,933.48625 c (US Legal) | 12,103.964625 c (US Legal) | 12,274.443 c (US Legal) | 12,444.921375 c (US Legal) | 12,615.39975 c (US Legal) | 12,785.878125 c (US Legal) | 12,956.3565 c (US Legal) | 13,126.834875 c (US Legal) | 13,297.31325 c (US Legal) | 13,467.791625 c (US Legal) | 13,638.27 c (US Legal) | 13,808.748375 c (US Legal) | 13,979.22675 c (US Legal) | 14,149.705125 c (US Legal) | 14,320.1835 c (US Legal) | 14,490.661875 c (US Legal) | 14,661.14025 c (US Legal) | 14,831.618625 c (US Legal) | 15,002.097 c (US Legal) | 15,172.575375 c (US Legal) | 15,343.05375 c (US Legal) | 15,513.532125 c (US Legal) | 15,684.0105 c (US Legal) | 15,854.488875 c (US Legal) | 16,024.96725 c (US Legal) | 16,195.445625 c (US Legal) | 16,365.924 c (US Legal) | 16,536.402375 c (US Legal) | 16,706.88075 c (US Legal) | 16,877.359125 c (US Legal) | 17,047.8375 c (US Legal) |
The ale or beer firkin (from Middle Dutch vierdekijn meaning "fourth") is a quarter of an ale or beer barrel or half a kilderkin. This unit is much smaller than the wine firkin. Casks in this size (themselves called firkins) are the most common container for cask ale.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| firkin | ≡ 9 gal (imp) | = 0.04091481 m3 | Imperial/US |
| firkins | US legal cups | firkins | US legal cups |
|---|---|---|---|
| 1 | = 170.478375 | 6 | = 1022.87025 |
| 2 | = 340.95675 | 7 | = 1193.348625 |
| 3 | = 511.435125 | 8 | = 1363.827 |
| 4 | = 681.9135 | 9 | = 1534.305375 |
| 5 | = 852.391875 | 10 | = 1704.78375 |
The cup currently used in the United States for nutrition labelling is defined in United States law as 240 ml.
| 1 U.S. "legal" cup | = | 240 | millilitres |
| = | 16 | international tablespoons | |
| = | 12 | Australian tablespoons | |
| ≈ | 8.12 | U.S. customary fluid ounces | |
| ≈ | 8.45 | imperial fluid ounces |
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| US legal cup | c (US Legal) | ≡ 240 mL | = 2.4×10−4 m3 | Imperial/US |
| US legal cups | firkins | US legal cups | firkins |
|---|---|---|---|
| 1 | = 0.005865846621309 | 6 | = 0.035195079727854 |
| 2 | = 0.011731693242618 | 7 | = 0.041060926349163 |
| 3 | = 0.017597539863927 | 8 | = 0.046926772970472 |
| 4 | = 0.023463386485236 | 9 | = 0.052792619591781 |
| 5 | = 0.029329233106545 | 10 | = 0.05865846621309 |
| firkins | US legal cups |
|---|---|
| 1 | = 170.478375 |
| 0.0058658 | = 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 …) |