| 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 |
| inch | 9 in | 18 in | 27 in | 36 in | 45 in | 54 in | 63 in | 72 in | 81 in | 90 in | 99 in | 108 in | 117 in | 126 in | 135 in | 144 in | 153 in | 162 in | 171 in | 180 in | 189 in | 198 in | 207 in | 216 in | 225 in | 234 in | 243 in | 252 in | 261 in | 270 in | 279 in | 288 in | 297 in | 306 in | 315 in | 324 in | 333 in | 342 in | 351 in | 360 in | 369 in | 378 in | 387 in | 396 in | 405 in | 414 in | 423 in | 432 in | 441 in | 450 in | 459 in | 468 in | 477 in | 486 in | 495 in | 504 in | 513 in | 522 in | 531 in | 540 in | 549 in | 558 in | 567 in | 576 in | 585 in | 594 in | 603 in | 612 in | 621 in | 630 in | 639 in | 648 in | 657 in | 666 in | 675 in | 684 in | 693 in | 702 in | 711 in | 720 in | 729 in | 738 in | 747 in | 756 in | 765 in | 774 in | 783 in | 792 in | 801 in | 810 in | 819 in | 828 in | 837 in | 846 in | 855 in | 864 in | 873 in | 882 in | 891 in | 900 in |
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 | inches | spans | inches |
|---|---|---|---|
| 1 | = 9 | 4 | = 36 |
| 1.5 | = 13.5 | 4.5 | = 40.5 |
| 2 | = 18 | 5 | = 45 |
| 2.5 | = 22.5 | 5.5 | = 49.5 |
| 3 | = 27 | 6 | = 54 |
The inch (abbreviation: in or ″) is a unit of length in the (British) imperial and United States customary systems of measurement now formally equal to 1⁄36 yard but usually understood as 1⁄12 of a foot. Derived from the Roman uncia ("twelfth"), inch is also sometimes used to translate related units in other measurement systems, usually understood as deriving from the width of the human thumb.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| inch | in | ≡ 2.54 cm ≡ 1⁄36 yd ≡ 1⁄12 ft | ≡ 0.0254 m | Imperial/US |
| inches | spans | inches | spans |
|---|---|---|---|
| 1 | = 0.11111111111111 | 4 | = 0.44444444444444 |
| 1.5 | = 0.16666666666667 | 4.5 | = 0.5 |
| 2 | = 0.22222222222222 | 5 | = 0.55555555555556 |
| 2.5 | = 0.27777777777778 | 5.5 | = 0.61111111111111 |
| 3 | = 0.33333333333333 | 6 | = 0.66666666666667 |
| spans | inches |
|---|---|
| 1 | = 9 |
| 0.1111111 | = 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 …) |