convertimate Catheter sizes (French)

Charrière to millimeters

Type a value in Ch to get it in mm instantly.

4.667mm

That's 1.75× as wide as an 8 Fr feeding tube, while a 16 Fr urinary catheter is 1.14× wider. Its circumference is about 14.66 mm.

What it means

How wide is that tube?

French gives the outer diameter. The inner lumen is smaller and depends on the wall thickness and material.

The math

How to convert Ch to mm

To convert Charrière to millimeters, multiply by 0.333333.

Example: 14 Ch × 0.333333 = 4.66667 mm.

In the other direction, 1 mm = 3 Ch.

Every unit

That tube size in every unit

Tables

Ch to mm conversion table

Ch to mm conversion table
Chmm
3 Ch1 mm
4 Ch1.33333 mm
5 Ch1.66667 mm
6 Ch2 mm
7 Ch2.33333 mm
8 Ch2.66667 mm
10 Ch3.33333 mm
12 Ch4 mm
14 Ch4.66667 mm
16 Ch5.33333 mm
18 Ch6 mm
20 Ch6.66667 mm
22 Ch7.33333 mm
24 Ch8 mm
28 Ch9.33333 mm
30 Ch10 mm
mm to Ch conversion table
mm to Ch conversion table
mmCh
3 mm9 Ch
4 mm12 Ch
5 mm15 Ch
6 mm18 Ch
7 mm21 Ch
8 mm24 Ch
10 mm30 Ch
12 mm36 Ch
14 mm42 Ch
16 mm48 Ch
18 mm54 Ch
20 mm60 Ch
22 mm66 Ch
24 mm72 Ch
28 mm84 Ch
30 mm90 Ch

Quick answers

Quick answers

How many mm is 1 Ch?
1 Ch is 0.333333 mm.
How many mm is 10 Ch?
10 Ch is 3.33333 mm.
How many mm is 14 Ch?
14 Ch is 4.66667 mm.

The units

About these units

Charrière (Ch)

The same scale under its inventor’s name, used across Europe.

Millimeters (mm)

Outer diameter in millimeters.

Learn more about tube size units

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