Measurement Conversions
Common Surgical Instrument Sizes
Do you need to convert millimeters to inches? Inches to centimeters? Ounces to grams? Perhaps you need to compare the diameters of various catheters, sounds or bougies using the French, English or American scales.
Stainless Steel Instruments
- Ten millimeters = one centimeter.
- To convert inches to centimeters, multiply inches in decimals by 2.54.
- To convert centimeters to inches, multiply centimeters by 0.3937.
- To convert millimeters to inches, multiply millimeters by 0.03937.
- The standard French, or Charriere, Scale (abbreviated Fr.) is generally used in the size calibration of catheters and other tubular instruments. It is based on the metric system, with each unit being approximately 0.33 mm in diameter between consecutive sizes.
Download Conversion Chart
Get our convenient, easy to understand, printable measurement conversion chart and your conversion problems will be solved in no time.
DownloadLiquid Conversion
| UOM | fluid oz. | quarts | gallons | ml | liters |
|---|---|---|---|---|---|
| Multiplier | 29.57 | 0.95 | 3.79 | 0.03 | 1.06, 0.26 |
| Converts To | ml | litres | liters | fluid oz. | quarts gallons |
COMPARATIVE SCALES OR GAUGES
Used in Measuring the Diameters of Catheters, Sounds and Bougies
| Diameters in MM | American | French | English |
|---|---|---|---|
| 1-3 | - | 1 | - |
| 1-2 | 1 | - | - |
| 2-3 | - | 2 | - |
| 1 | 2 | 3 | - |
| 11-3 | - | 4 | - |
| 11-2 | 3 | - | - |
| 12-3 | - | 5 | - |
| 2 | 4 | 5 | - |
| 21-3 | - | 7 | 1 |
| 21-2 | 5 | - | - |
| 22-3 | - | 8 | 2 |
| 3 | 6 | 9 | 3 |
| 31-3 | - | 10 | - |
| 31-2 | 7 | - | - |
| 32-3 | - | 11 | 4 |
| 4 | 8 | 12 | 5 |
| 41-3 | - | 13 | - |
| 41-2 | 9 | - | - |
| 42-3 | - | 14 | - |
| 5 | 10 | 15 | 6 |
| 51-3 | - | 16 | 7 |
| 51-2 | 11 | - | - |
| 52-3 | - | 17 | 8 |
| 6 | 12 | 18 | 9 |
| 61-3 | - | 19 | 10 |
| 61-2 | 13 | - | - |
| 62-3 | - | 20 | 11 |
| Diameters in MM | American | French | English |
|---|---|---|---|
| 7 | 14 | 21 | - |
| 71-3 | 1 | 22 | 12 |
| 71-2 | 15 | - | - |
| 72-3 | - | 23 | 13 |
| 8 | 16 | 24 | - |
| 81-3 | - | 25 | 14 |
| 81-2 | 17 | - | - |
| 82-3 | - | 26 | 15 |
| 9 | 18 | 27 | 16 |
| 91-3 | - | 28 | 17 |
| 91-2 | 19 | - | - |
| 92-3 | - | 29 | - |
| 10 | 20 | 30 | 18 |
| 101-3 | - | 31 | 19 |
| 101-2 | 21 | - | - |
| 102-3 | - | 32 | 20 |
| 11 | 22 | 33 | 21 |
| 111-3 | - | 34 | 22 |
| 111-2 | 23 | - | - |
| 112-3 | - | 35 | 23 |
| 12 | 24 | 36 | 24 |
| 121-3 | - | 37 | 25 |
| 121-2 | 25 | - | - |
| 122-3 | - | 38 | 26 |
| 13 | 26 | 39 | 27 |
| 131-3 | - | 40 | 28 |