| french; charriere | 1 F | 2 F | 3 F | 4 F | 5 F | 6 F | 7 F | 8 F | 9 F | 10 F | 11 F | 12 F | 13 F | 14 F | 15 F | 16 F | 17 F | 18 F | 19 F | 20 F | 21 F | 22 F | 23 F | 24 F | 25 F | 26 F | 27 F | 28 F | 29 F | 30 F | 31 F | 32 F | 33 F | 34 F | 35 F | 36 F | 37 F | 38 F | 39 F | 40 F | 41 F | 42 F | 43 F | 44 F | 45 F | 46 F | 47 F | 48 F | 49 F | 50 F | 51 F | 52 F | 53 F | 54 F | 55 F | 56 F | 57 F | 58 F | 59 F | 60 F | 61 F | 62 F | 63 F | 64 F | 65 F | 66 F | 67 F | 68 F | 69 F | 70 F | 71 F | 72 F | 73 F | 74 F | 75 F | 76 F | 77 F | 78 F | 79 F | 80 F | 81 F | 82 F | 83 F | 84 F | 85 F | 86 F | 87 F | 88 F | 89 F | 90 F | 91 F | 92 F | 93 F | 94 F | 95 F | 96 F | 97 F | 98 F | 99 F | 100 F |
| span | 0.0014582 span | 0.0029163 span | 0.0043745 span | 0.0058326 span | 0.0072908 span | 0.0087489 span | 0.0102071 span | 0.0116652 span | 0.0131234 span | 0.0145815 span | 0.0160397 span | 0.0174978 span | 0.0189560 span | 0.0204141 span | 0.0218723 span | 0.0233304 span | 0.0247886 span | 0.0262467 span | 0.0277049 span | 0.0291630 span | 0.0306212 span | 0.0320793 span | 0.0335375 span | 0.0349956 span | 0.0364538 span | 0.0379119 span | 0.0393701 span | 0.0408282 span | 0.0422864 span | 0.0437445 span | 0.0452027 span | 0.0466608 span | 0.0481190 span | 0.0495771 span | 0.0510353 span | 0.0524934 span | 0.0539516 span | 0.0554097 span | 0.0568679 span | 0.0583260 span | 0.0597842 span | 0.0612423 span | 0.0627005 span | 0.0641586 span | 0.0656168 span | 0.0670749 span | 0.0685331 span | 0.0699913 span | 0.0714494 span | 0.0729076 span | 0.0743657 span | 0.0758239 span | 0.0772820 span | 0.0787402 span | 0.0801983 span | 0.0816565 span | 0.0831146 span | 0.0845728 span | 0.0860309 span | 0.0874891 span | 0.0889472 span | 0.0904054 span | 0.0918635 span | 0.0933217 span | 0.0947798 span | 0.0962380 span | 0.0976961 span | 0.0991543 span | 0.1006124 span | 0.1020706 span | 0.1035287 span | 0.1049869 span | 0.1064450 span | 0.1079032 span | 0.1093613 span | 0.1108195 span | 0.1122776 span | 0.1137358 span | 0.1151939 span | 0.1166521 span | 0.1181102 span | 0.1195684 span | 0.1210265 span | 0.1224847 span | 0.1239428 span | 0.1254010 span | 0.1268591 span | 0.1283173 span | 0.1297754 span | 0.1312336 span | 0.1326917 span | 0.1341499 span | 0.1356080 span | 0.1370662 span | 0.1385244 span | 0.1399825 span | 0.1414407 span | 0.1428988 span | 0.1443570 span | 0.1458151 span |
The French scale or French gauge system is commonly used to measure the size of a catheter. It is most often abbreviated as Fr, but can often be seen abbreviated as Fg, Ga, FR or F. It may also be abbreviated as CH or Ch (for Charrière, its inventor).
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| french; charriere | F | ≡ 1⁄3 mm | = 0.3×10−3 m | Other (Length) |
| french; charriere | spans | french; charriere | spans |
|---|---|---|---|
| 1 | = 0.0014581510644503 | 4 | = 0.0058326042578011 |
| 1.5 | = 0.0021872265966754 | 4.5 | = 0.0065616797900262 |
| 2 | = 0.0029163021289006 | 5 | = 0.0072907553222514 |
| 2.5 | = 0.0036453776611257 | 5.5 | = 0.0080198308544765 |
| 3 | = 0.0043744531933508 | 6 | = 0.0087489063867017 |
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 | french; charriere | spans | french; charriere |
|---|---|---|---|
| 1 | = 685.8 | 4 | = 2743.2 |
| 1.5 | = 1028.7 | 4.5 | = 3086.1 |
| 2 | = 1371.6 | 5 | = 3429 |
| 2.5 | = 1714.5 | 5.5 | = 3771.9 |
| 3 | = 2057.4 | 6 | = 4114.8 |
| french; charriere | spans |
|---|---|
| 1 | = 0.0014582 |
| 685.8 | = 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 …) |