Unit conversions
Unit Converter
Convert French cannula size and everyday measurement units. French size refers to outer diameter.
Converted result
Choose the units and enter a value to convert.
Example: 24 Fr = 8 mm = 0.8 cm outer diameter. Fr (French) is also called Ch (Charrière). Check the manufacturer’s dimensions for the specific device.
References & notes
French size is a diameter scale. It is not a gauge number, a lumen measurement, or a flow rating. The calculation does not round to a marketed cannula size.
A day in the unit converter is exactly 24 hours. Use ECMO Duration for dates and times.
- MSF: French / Charrière outer-diameter scale
- BIPM: The International System of Units
- NIST: Conversion factors
- NIST: General tables of units of measurement
Conversion version 1.0