| millimeter | 1 mm | 2 mm | 3 mm | 4 mm | 5 mm | 6 mm | 7 mm | 8 mm | 9 mm | 10 mm | 11 mm | 12 mm | 13 mm | 14 mm | 15 mm | 16 mm | 17 mm | 18 mm | 19 mm | 20 mm | 21 mm | 22 mm | 23 mm | 24 mm | 25 mm | 26 mm | 27 mm | 28 mm | 29 mm | 30 mm | 31 mm | 32 mm | 33 mm | 34 mm | 35 mm | 36 mm | 37 mm | 38 mm | 39 mm | 40 mm | 41 mm | 42 mm | 43 mm | 44 mm | 45 mm | 46 mm | 47 mm | 48 mm | 49 mm | 50 mm | 51 mm | 52 mm | 53 mm | 54 mm | 55 mm | 56 mm | 57 mm | 58 mm | 59 mm | 60 mm | 61 mm | 62 mm | 63 mm | 64 mm | 65 mm | 66 mm | 67 mm | 68 mm | 69 mm | 70 mm | 71 mm | 72 mm | 73 mm | 74 mm | 75 mm | 76 mm | 77 mm | 78 mm | 79 mm | 80 mm | 81 mm | 82 mm | 83 mm | 84 mm | 85 mm | 86 mm | 87 mm | 88 mm | 89 mm | 90 mm | 91 mm | 92 mm | 93 mm | 94 mm | 95 mm | 96 mm | 97 mm | 98 mm | 99 mm | 100 mm |
| french; charriere | 3 F | 6 F | 9 F | 12 F | 15 F | 18 F | 21 F | 24 F | 27 F | 30 F | 33 F | 36 F | 39 F | 42 F | 45 F | 48 F | 51 F | 54 F | 57 F | 60 F | 63 F | 66 F | 69 F | 72 F | 75 F | 78 F | 81 F | 84 F | 87 F | 90 F | 93 F | 96 F | 99 F | 102 F | 105 F | 108 F | 111 F | 114 F | 117 F | 120 F | 123 F | 126 F | 129 F | 132 F | 135 F | 138 F | 141 F | 144 F | 147 F | 150 F | 153 F | 156 F | 159 F | 162 F | 165 F | 168 F | 171 F | 174 F | 177 F | 180 F | 183 F | 186 F | 189 F | 192 F | 195 F | 198 F | 201 F | 204 F | 207 F | 210 F | 213 F | 216 F | 219 F | 222 F | 225 F | 228 F | 231 F | 234 F | 237 F | 240 F | 243 F | 246 F | 249 F | 252 F | 255 F | 258 F | 261 F | 264 F | 267 F | 270 F | 273 F | 276 F | 279 F | 282 F | 285 F | 288 F | 291 F | 294 F | 297 F | 300 F |
The millimetre (International spelling as used by the International Bureau of Weights and Measures; SI unit symbol mm) or millimeter (American spelling) is a unit of length in the metric system, equal to one thousandth of a metre, which is the SI base unit of length. Therefore there are thousand millimetres in a metre. There are ten millimetres in a centimetre.
| 1 millimeters = 3 french; charriere | 4 millimeters = 12 french; charriere |
| 1.5 millimeters = 4.5 french; charriere | 4.5 millimeters = 13.5 french; charriere |
| 2 millimeters = 6 french; charriere | 5 millimeters = 15 french; charriere |
| 2.5 millimeters = 7.5 french; charriere | 5.5 millimeters = 16.5 french; charriere |
| 3 millimeters = 9 french; charriere | 6 millimeters = 18 french; charriere |
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).
| 1 french; charriere = 0.33333333333333 millimeters | 4 french; charriere = 1.3333333333333 millimeters |
| 1.5 french; charriere = 0.5 millimeters | 4.5 french; charriere = 1.5 millimeters |
| 2 french; charriere = 0.66666666666667 millimeters | 5 french; charriere = 1.6666666666667 millimeters |
| 2.5 french; charriere = 0.83333333333333 millimeters | 5.5 french; charriere = 1.8333333333333 millimeters |
| 3 french; charriere = 1 millimeters | 6 french; charriere = 2 millimeters |
| 1 millimeters = 3 french; charriere |
| 1 french; charriere = 0.3333333 millimeters |