| 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 |
| foot | 0.75 ft | 1.5 ft | 2.25 ft | 3 ft | 3.75 ft | 4.5 ft | 5.25 ft | 6 ft | 6.75 ft | 7.5 ft | 8.25 ft | 9 ft | 9.75 ft | 10.5 ft | 11.25 ft | 12 ft | 12.75 ft | 13.5 ft | 14.25 ft | 15 ft | 15.75 ft | 16.5 ft | 17.25 ft | 18 ft | 18.75 ft | 19.5 ft | 20.25 ft | 21 ft | 21.75 ft | 22.5 ft | 23.25 ft | 24 ft | 24.75 ft | 25.5 ft | 26.25 ft | 27 ft | 27.75 ft | 28.5 ft | 29.25 ft | 30 ft | 30.75 ft | 31.5 ft | 32.25 ft | 33 ft | 33.75 ft | 34.5 ft | 35.25 ft | 36 ft | 36.75 ft | 37.5 ft | 38.25 ft | 39 ft | 39.75 ft | 40.5 ft | 41.25 ft | 42 ft | 42.75 ft | 43.5 ft | 44.25 ft | 45 ft | 45.75 ft | 46.5 ft | 47.25 ft | 48 ft | 48.75 ft | 49.5 ft | 50.25 ft | 51 ft | 51.75 ft | 52.5 ft | 53.25 ft | 54 ft | 54.75 ft | 55.5 ft | 56.25 ft | 57 ft | 57.75 ft | 58.5 ft | 59.25 ft | 60 ft | 60.75 ft | 61.5 ft | 62.25 ft | 63 ft | 63.75 ft | 64.5 ft | 65.25 ft | 66 ft | 66.75 ft | 67.5 ft | 68.25 ft | 69 ft | 69.75 ft | 70.5 ft | 71.25 ft | 72 ft | 72.75 ft | 73.5 ft | 74.25 ft | 75 ft |
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).
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| span | span | ≡ 9 in | = 0.2286 m | Imperial/US |
| spans | feet | spans | feet |
|---|---|---|---|
| 1 | = 0.75 | 4 | = 3 |
| 1.5 | = 1.125 | 4.5 | = 3.375 |
| 2 | = 1.5 | 5 | = 3.75 |
| 2.5 | = 1.875 | 5.5 | = 4.125 |
| 3 | = 2.25 | 6 | = 4.5 |
The foot (pl. feet; abbreviation: ft; symbol: ′, the prime symbol) is a unit of length in the imperial and US customary systems of measurement. Since 1959, both units have been defined by international agreement as equivalent to 0.3048 meters exactly. In both systems, the foot comprises 12 inches and three feet compose a yard.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| foot | ft | ≡ 0.3048 m ≡ 1⁄3 yd ≡ 12 inches | ≡ 0.3048 m | Imperial/US |
| feet | spans | feet | spans |
|---|---|---|---|
| 1 | = 1.3333333333333 | 4 | = 5.3333333333333 |
| 1.5 | = 2 | 4.5 | = 6 |
| 2 | = 2.6666666666667 | 5 | = 6.6666666666667 |
| 2.5 | = 3.3333333333333 | 5.5 | = 7.3333333333333 |
| 3 | = 4 | 6 | = 8 |
| spans | feet |
|---|---|
| 1 | = 0.75 |
| 1.3333333 | = 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 …) |