# 23s gauge needle — Hypodermic needle gauge dimensions (OD, ID, wall thickness, dead volume) For 23s gauge needle, nominal o.d. (mm) is 0.642; nominal i.d. (mm) is 0.116; wall thickness (mm) is 0.267; dead volume (ul per 25.4 mm) is 0.268 µL/25.4 mm, verified against its source on 2026-08-27. - **Gauge number:** 23s gauge needle _(verified: appears in the quote below)_ - **Nominal O.D. (mm):** 0.642 _(verified: appears in the quote below)_ - **Nominal I.D. (mm):** 0.116 _(verified: appears in the quote below)_ - **Wall thickness (mm):** 0.267 _(verified: appears in the quote below)_ - **Dead volume (uL per 25.4 mm):** 0.268 µL/25.4 mm _(verified: appears in the quote below)_ ## What the source says > 23s gauge needle | 0.642 | 0.116 | 0.267 | 0.268 µL/25.4 mm ## Source - https://www.hamiltoncompany.com/laboratory-products/needles-knowledge/needle-gauge-chart Last verified: 2026-08-27. Review by: 2029-08-26. Part of [Hypodermic needle gauge dimensions (OD, ID, wall thickness, dead volume)](https://referencesource.org/syringe-needle-gauge-dimensions/).