Gauge Index

When selecting a needle gauge 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 gauge index to choose a needle gauge with an appropriate µL/inch before selecting a needle. Select the minimum 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.

 Nominal O.D. Nominal I.D. Wall Thickness Volume Gauge Inch mm* Inch mm* Inch mm* µL/Inch 34 0.0060 - 0.0065 0.159 0.0015 - 0.0025 0.051 0.004 0.11 0.052 33 0.0080 - 0.0085 0.210 0.0035 - 0.0050 0.108 0.004 0.10 0.233 32 0.0090 - 0.0095 0.235 0.0035 - 0.0050 0.108 0.005 0.13 0.233 31 0.0100 - 0.0105 0.261 0.0045 - 0.0060 0.133 0.005 0.13 0.353 30 0.0120 - 0.0125 0.312 0.0055 - 0.0070 0.159 0.006 0.15 0.504 29 0.0130 - 0.0135 0.337 0.0065 - 0.0080 0.184 0.006 0.15 0.675 28 0.0140 - 0.0145 0.362 0.0065 - 0.0080 0.184 0.007 0.18 0.675 27 0.0160 - 0.0165 0.413 0.0075 - 0.0090 0.210 0.008 0.20 0.876 26s 0.0184 - 0.0189 0.474 0.0045 - 0.0055 0.127 0.014 0.35 0.322 26 0.0180 - 0.0185 0.464 0.0095 - 0.0110 0.260 0.008 0.20 1.349 25s 0.0200 - 0.0205 0.515 0.0055 - 0.0065 0.153 0.014 0.36 0.464 25 0.0200 - 0.0205 0.515 0.0095 - 0.0110 0.260 0.010 0.25 1.349 24 0.0220 - 0.0225 0.566 0.0115 - 0.0130 0.311 0.010 0.25 1.930 23s 0.0250 - 0.0255 0.642 0.0040 - 0.0051 0.116 0.021 0.53 0.268 23 0.0250 - 0.0255 0.642 0.0125 - 0.0140 0.337 0.012 0.30 2.266 22s 0.0280 - 0.0285 0.718 0.0055 - 0.0077 0.168 0.022 0.55 0.563 22 0.0280 - 0.0285 0.718 0.0155 - 0.0170 0.413 0.012 0.30 3.403 21 0.0320 - 0.0325 0.819 0.0195 - 0.0210 0.514 0.012 0.30 5.271 20 0.0355 - 0.0360 0.908 0.0230 - 0.0245 0.603 0.012 0.30 7.255 19 0.0415 - 0.0425 1.067 0.0255 - 0.0285 0.686 0.015 0.38 9.389 18 0.0495 - 0.0505 1.270 0.0315 - 0.0345 0.838 0.017 0.43 14.011 17 0.0575 - 0.0585 1.473 0.0405 - 0.0435 1.067 0.016 0.41 22.715 16 0.0645 - 0.0655 1.651 0.0455 - 0.0485 1.194 0.018 0.46 28.444 15 0.0715 - 0.0725 1.829 0.0525 - 0.0555 1.372 0.018 0.46 37.529 14 0.0820 - 0.0840 2.109 0.0610 - 0.0650 1.600 0.020 0.51 51.076 13 0.0940 - 0.0960 2.413 0.0690 - 0.0730 1.804 0.024 0.61 64.895 12 0.1080 - 0.110 2.769 0.0830 - 0.0870 2.159 0.024 0.61 93.000 11 0.1190 - 0.1210 3.048 0.0920 - 0.0960 2.388 0.026 0.66 113.728 10 0.1330 - 0.1350 3.404 0.1040 - 0.1080 2.693 0.028 0.71 144.641
*mm are nominal
Hamilton Company USA
4970 Energy Way