| span | 1 span | 2 span | 3 span | 4 span | 5 span | 6 span | 7 span | 8 span | 9 span | 10 span | 11 span | 12 span | 13 span | 14 span | 15 span | 16 span | 17 span | 18 span | 19 span | 20 span | 21 span | 22 span | 23 span | 24 span | 25 span | 26 span | 27 span | 28 span | 29 span | 30 span | 31 span | 32 span | 33 span | 34 span | 35 span | 36 span | 37 span | 38 span | 39 span | 40 span | 41 span | 42 span | 43 span | 44 span | 45 span | 46 span | 47 span | 48 span | 49 span | 50 span | 51 span | 52 span | 53 span | 54 span | 55 span | 56 span | 57 span | 58 span | 59 span | 60 span | 61 span | 62 span | 63 span | 64 span | 65 span | 66 span | 67 span | 68 span | 69 span | 70 span | 71 span | 72 span | 73 span | 74 span | 75 span | 76 span | 77 span | 78 span | 79 span | 80 span | 81 span | 82 span | 83 span | 84 span | 85 span | 86 span | 87 span | 88 span | 89 span | 90 span | 91 span | 92 span | 93 span | 94 span | 95 span | 96 span | 97 span | 98 span | 99 span | 100 span |
| fathom | 0.125 ftm | 0.25 ftm | 0.375 ftm | 0.5 ftm | 0.625 ftm | 0.75 ftm | 0.875 ftm | 1 ftm | 1.125 ftm | 1.25 ftm | 1.375 ftm | 1.5 ftm | 1.625 ftm | 1.75 ftm | 1.875 ftm | 2 ftm | 2.125 ftm | 2.25 ftm | 2.375 ftm | 2.5 ftm | 2.625 ftm | 2.75 ftm | 2.875 ftm | 3 ftm | 3.125 ftm | 3.25 ftm | 3.375 ftm | 3.5 ftm | 3.625 ftm | 3.75 ftm | 3.875 ftm | 4 ftm | 4.125 ftm | 4.25 ftm | 4.375 ftm | 4.5 ftm | 4.625 ftm | 4.75 ftm | 4.875 ftm | 5 ftm | 5.125 ftm | 5.25 ftm | 5.375 ftm | 5.5 ftm | 5.625 ftm | 5.75 ftm | 5.875 ftm | 6 ftm | 6.125 ftm | 6.25 ftm | 6.375 ftm | 6.5 ftm | 6.625 ftm | 6.75 ftm | 6.875 ftm | 7 ftm | 7.125 ftm | 7.25 ftm | 7.375 ftm | 7.5 ftm | 7.625 ftm | 7.75 ftm | 7.875 ftm | 8 ftm | 8.125 ftm | 8.25 ftm | 8.375 ftm | 8.5 ftm | 8.625 ftm | 8.75 ftm | 8.875 ftm | 9 ftm | 9.125 ftm | 9.25 ftm | 9.375 ftm | 9.5 ftm | 9.625 ftm | 9.75 ftm | 9.875 ftm | 10 ftm | 10.125 ftm | 10.25 ftm | 10.375 ftm | 10.5 ftm | 10.625 ftm | 10.75 ftm | 10.875 ftm | 11 ftm | 11.125 ftm | 11.25 ftm | 11.375 ftm | 11.5 ftm | 11.625 ftm | 11.75 ftm | 11.875 ftm | 12 ftm | 12.125 ftm | 12.25 ftm | 12.375 ftm | 12.5 ftm |
A span is the distance measured by a human hand, from the tip of the thumb to the tip of the little finger. In ancient times, a span was considered to be half a cubit. Sometimes the distinction is made between the great span (thumb to little finger) and little span (index finger to little finger).
| 1 spans = 0.125 fathoms | 4 spans = 0.5 fathoms |
| 1.5 spans = 0.1875 fathoms | 4.5 spans = 0.5625 fathoms |
| 2 spans = 0.25 fathoms | 5 spans = 0.625 fathoms |
| 2.5 spans = 0.3125 fathoms | 5.5 spans = 0.6875 fathoms |
| 3 spans = 0.375 fathoms | 6 spans = 0.75 fathoms |
A fathom is a unit of length in the imperial and the U.S. customary systems equal to 6 feet (1.8288 metres), used especially for measuring the depth of water.
There are two yards (6 feet) in an imperial fathom. Originally the span of a man's outstretched arms, the size of a fathom has varied slightly depending on whether it was defined as a thousandth of an (Admiralty) nautical mile or as a multiple of the imperial yard. Formerly, the term was used for any of several units of length varying around 5–5 1⁄2 feet.
| 1 fathoms = 8 spans | 4 fathoms = 32 spans |
| 1.5 fathoms = 12 spans | 4.5 fathoms = 36 spans |
| 2 fathoms = 16 spans | 5 fathoms = 40 spans |
| 2.5 fathoms = 20 spans | 5.5 fathoms = 44 spans |
| 3 fathoms = 24 spans | 6 fathoms = 48 spans |
| 1 spans = 0.125 fathoms |
| 1 fathoms = 8 spans |