When selecting needle gauge sizes, it is important to keep in mind the volume of the syringe and the dead volume of the needle. For example, it will be very difficult to prime a 10 µL syringe if the dead volume in the needle is greater than 10 µL. Refer to the needle gauge chart to choose a needle gauge with an appropriate µL/inch before selecting a needle. Select the minimum needle length that allows you to carry out your application comfortably.

Note: The ‘s’ on a 22s needle represents a smaller I.D. (inner diameter) for the needle and a thicker needle wall for better durability. For example, a 26 gauge needle has an O.D. (outer diameter) of 0.46 mm and an I.D. of 0.26 mm, while the 26s gauge needle has an O.D. of 0.47 mm and an I.D. of 0.13 mm. The 26s has half the I.D. of the 26 gauge needle. Also, the difference in the wall thickness nearly doubles, with 26s gauge having a thickness of 0.18 mm while the 26 gauge is only 0.10 mm.

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Common Applications	Gauge Number	Needle Nominal O.D. (mm)	Needle Nominal I.D. (mm)	Needle Wall Thickness (mm)	Needle Dead Volume (µL/25.4mm)
Life Science	34 gauge needle	0.159	0.051	0.051	0.052 µL/25.4 mm
	33 gauge needle	0.21	0.108	0.051	0.233 µL/25.4 mm
	32 gauge needle	0.235	0.108	0.064	0.233 µL/25.4 mm
	31 gauge needle	0.261	0.133	0.064	0.353 µL/25.4 mm
	30 gauge needle	0.312	0.159	0.076	0.504 µL/25.4 mm
	29 gauge needle	0.337	0.184	0.076	0.675 µL/25.4mm
	28 gauge needle	0.362	0.184	0.089	0.675 µL/25.4 mm
	27 gauge needle	0.413	0.21	0.102	0.876 µL/25.4 mm
Chromatography	26s gauge needle	0.474	0.127	0.178	0.322 µL/25.4 mm
	26 gauge needle	0.464	0.26	0.102	1.349 µL/25.4 mm
	25s gauge needle	0.515	0.153	0.178	0.464 µL/25.4 mm
	25 gauge needle	0.515	0.26	0.127	1.349 µL/25.4 mm
	24 gauge needle	0.566	0.311	0.127	1.93 µL/25.4 mm
	23s gauge needle	0.642	0.116	0.267	0.268 µL/25.4 mm
	23 gauge needle	0.642	0.337	0.152	2.266 µL/25.4 mm
	22s gauge needle	0.718	0.168	0.279	0.563 µL/25.4 mm
	22 gauge needle	0.718	0.413	0.152	3.403 µL/25.4 mm
General Fluid Handling	21 gauge needle	0.819	0.514	0.152	5.271 µL/25.4 mm
	20 gauge needle	0.908	0.603	0.152	7.255 µL/25.4 mm
	19 gauge needle	1.067	0.686	0.191	9.389 µL/25.4 mm
	18 gauge needle	1.27	0.838	0.216	14.011 µL/25.4 mm
	17 gauge needle	1.473	1.067	0.203	22.715 µL/25.4 mm
	16 gauge needle	1.651	1.194	0.229	28.444 µL/25.4 mm
	15 gauge needle	1.829	1.372	0.229	37.529 µL/25.4 mm
	14 gauge needle	2.109	1.6	0.254	51.076 µL/25.4 mm
	13 gauge needle	2.413	1.804	0.305	64.895 µL/25.4 mm
	12 gauge needle	2.769	2.159	0.305	93 µL/25.4 mm
	11 gauge needle	3.048	2.388	0.33	113.728 µL/25.4 mm
	10 gauge needle	3.404	2.693	0.356	144.641 µL/25.4 mm
	*mm are nominal

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