Catheter Sizes

The French scale or French gauge system (most correctly abbreviated as Fr, but also often abbreviated as FR or F) is commonly used to measure the size (diameter) of a catheter.

An increasing French size corresponds to a larger-diameter catheter.

When ordering your O'Neil intermittent catheter, please tell us the French size you would like: 8, 10, 12, 14, or 16Fr.

Order here

French Gauge	Diameter (mm)	Diameter (inches)
3	1	0.039
4	1.35	0.053
5	1.67	0.066
6	2	0.079
7	2.3	0.092
8	2.7	0.105
9	3	0.118
10	3.3	0.131
11	3.7	0.144
12	4	0.158
13	4.3	0.170
14	4.7	0.184
15	5	0.197
16	5.3	0.210
17	5.7	0.223
18	6	0.236
19	6.3	0.249
20	6.7	0.263
22	7.3	0.288
24	8	0.315
26	8.7	0.341
28	9.3	0.367
30	10	0.393
32	10.7	0.419
34	11.3	0.445