This article is about hypodermic needles. For knitting needles, see
Knitting needle § Needle sizes and conversions.
Hypodermic needles are available in a wide variety of outer diameters described by gauge numbers. Smaller gauge numbers indicate larger outer diameters. Inner diameter depends on both gauge and wall thickness. The following chart shows nominal inner diameter and wall thickness for regular-wall needles. Thin-wall needles (not shown) have identical outer diameters but larger inner diameters for a given gauge.
Needle wire gauge is derived from the
Birmingham Wire Gauge. #1 = 18? B.W.G.; #2 = 19 B.W.G., and so on to #14 = 31 B.W.G.
NeedleNominal outer diameterNominal inner diameterNominal wall thickness
Gaugeinchesmmtol. inches (mm)inchesmmtol. inches (mm)inchesmmtol. inches (mm)
70.1804.572±0.001 (±0.025)0.1503.810±0.003 (±0.076)0.0150.381±0.001 (±0.025)
80.1654.191±0.001 (±0.025)0.1353.429±0.003 (±0.076)0.0150.381±0.001 (±0.025)
90.1483.759±0.001 (±0.025)0.1182.997±0.003 (±0.076)0.0150.381±0.001 (±0.025)
100.1343.404±0.001 (±0.025)0.1062.692±0.003 (±0.076)0.0140.356±0.001 (±0.025)
110.1203.048±0.001 (±0.025)0.0942.388±0.003 (±0.076)0.0130.330±0.001 (±0.025)
120.1092.769±0.001 (±0.025)0.0852.159±0.003 (±0.076)0.0120.305±0.001 (±0.025)
130.0952.413±0.001 (±0.025)0.0711.803±0.003 (±0.076)0.0120.305±0.001 (±0.025)
140.0832.108±0.001 (±0.025)0.0631.600±0.003 (±0.076)0.010.254±0.001 (±0.025)
150.0721.829±0.0005 (±0.013)0.0541.372±0.0015 (±0.038)0.0090.229±0.0005 (±0.013)
160.0651.651±0.0005 (±0.013)0.0471.194±0.0015 (±0.038)0.0090.229±0.0005 (±0.013)
170.0581.473±0.0005 (±0.013)0.0421.067±0.0015 (±0.038)0.0080.203±0.0005 (±0.013)
180.0501.270±0.0005 (±0.013)0.0330.838±0.0015 (±0.038)0.00850.216±0.0005 (±0.013)
190.0421.067±0.0005 (±0.013)0.0270.686±0.0015 (±0.038)0.00750.191±0.0005 (±0.013)
200.035750.9081±0.00025 (±0.0064)0.023750.603±0.00075 (±0.019)0.0060.1524±0.00025 (±0.0064)
210.032250.8192±0.00025 (±0.0064)0.020250.514±0.00075 (±0.019)0.0060.1524±0.00025 (±0.0064)
220.028250.7176±0.00025 (±0.0064)0.016250.413±0.00075 (±0.019)0.0060.1524±0.00025 (±0.0064)
22s0.028250.7176±0.00025 (±0.0064)0.0060.152±0.00075 (±0.019)0.01110.2826±0.00025 (±0.0064)
230.025250.6414±0.00025 (±0.0064)0.013250.337±0.00075 (±0.019)0.0060.1524±0.00025 (±0.0064)
240.022250.5652±0.00025 (±0.0064)0.012250.311±0.00075 (±0.019)0.0050.1270±0.00025 (±0.0064)
250.020250.5144±0.00025 (±0.0064)0.010250.260±0.00075 (±0.019)0.0050.1270±0.00025 (±0.0064)
260.018250.4636±0.00025 (±0.0064)0.010250.260±0.00075 (±0.019)0.0040.1016±0.00025 (±0.0064)
26s0.018650.4737±0.00025 (±0.0064)0.0050.127±0.00075 (±0.019)0.00680.1734±0.00025 (±0.0064)
270.016250.4128±0.00025 (±0.0064)0.008250.210±0.00075 (±0.019)0.0040.1016±0.00025 (±0.0064)
280.014250.3620±0.00025 (±0.0064)0.007250.184±0.00075 (±0.019)0.00350.0889±0.00025 (±0.0064)
290.013250.3366±0.00025 (±0.0064)0.007250.184±0.00075 (±0.019)0.0030.0762±0.00025 (±0.0064)
300.012250.3112±0.00025 (±0.0064)0.006250.159±0.00075 (±0.019)0.0030.0762±0.00025 (±0.0064)
310.010250.2604±0.00025 (±0.0064)0.005250.133±0.00075 (±0.019)0.00250.0635±0.00025 (±0.0064)
320.009250.2350±0.00025 (±0.0064)0.004250.108±0.00075 (±0.019)0.00250.0635±0.00025 (±0.0064)
330.008250.2096±0.00025 (±0.0064)0.004250.108±0.00075 (±0.019)0.0020.0508±0.00025 (±0.0064)
340.007250.1842±0.00025 (±0.0064)0.003250.0826±0.00075 (±0.019)0.0020.0508±0.00025 (±0.0064)
See also
EditFrench catheter scale chartStubs Needle GaugeReferences
Edit^
'Syringe Needle Gauge Chart'. Sigma Aldrich. Retrieved 20 March 2012.
'Hypodermic Needle Gauge Chart'. Medical Tube Technology, Inc. Retrieved 20 March 2012.