Gauge to millimeters
Type a value in G to get it in mm instantly.
0.718mm
That's 1.39× as thick as a 25 G vaccination needle, while a 21 G blood-test needle is 1.14× thicker. That is about 10.26 times the thickness of a human hair.
Convert the other way: mm to G
What it means
How thick is that needle?
Nominal outer diameters from the ISO 9626 table. Thin-wall and regular-wall needles of the same gauge share the outside diameter but differ inside.
The math
How to convert G to mm
Gauge is a table, not a formula: 21 G = 0.819 mm, 23 G = 0.642 mm, and values between gauges are interpolated.
Example: 22 G = 0.718 mm.
Every unit
That needle in every unit
Tables
G to mm conversion table
| G | mm |
|---|---|
| 14 G | 2.108 mm |
| 16 G | 1.651 mm |
| 18 G | 1.27 mm |
| 19 G | 1.067 mm |
| 20 G | 0.908 mm |
| 21 G | 0.819 mm |
| 22 G | 0.718 mm |
| 23 G | 0.642 mm |
| 24 G | 0.566 mm |
| 25 G | 0.515 mm |
| 26 G | 0.464 mm |
| 27 G | 0.413 mm |
| 28 G | 0.362 mm |
| 29 G | 0.337 mm |
| 30 G | 0.312 mm |
| 31 G | 0.261 mm |
| 32 G | 0.235 mm |
mm to G conversion table
| mm | G |
|---|---|
| 0.235 mm | 32 G |
| 0.261 mm | 31 G |
| 0.312 mm | 30 G |
| 0.337 mm | 29 G |
| 0.362 mm | 28 G |
| 0.413 mm | 27 G |
| 0.464 mm | 26 G |
| 0.515 mm | 25 G |
| 0.566 mm | 24 G |
| 0.642 mm | 23 G |
| 0.718 mm | 22 G |
| 0.819 mm | 21 G |
| 0.908 mm | 20 G |
| 1.07 mm | 18.9852 G |
| 1.27 mm | 18 G |
| 1.65 mm | 16.0056 G |
| 2.11 mm | 13.9934 G |
Quick answers
Quick answers
- How many mm is 10 G?
- 10 G is 3.404 mm.
- How many mm is 22 G?
- 22 G is 0.718 mm.
The units
About these units
Gauge (G)
The Birmingham/Stubs number printed on the hub.
Millimeters (mm)
Nominal outer diameter.
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