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Evaluate standard 19 gauge (0.0420" OD) hypotubes. Use our calculator to compare regular, thin, and extra-thin walls, balancing internal clearance, flow rate, and structural stiffness for your device design.
Compare standard 19 gauge wall categories (RW, TW, XTW, UTW) or input custom parameters to estimate lumen area, fluid flow efficiency, and structural stiffness.
Calculations use fixed nominal OD: 0.0420" (1.067 mm).
Flow efficiency is a proxy based on Poiseuille's law (proportional to ID⁴), referenced against Regular Wall (RW). Stiffness proxy relies on moment of inertia.
Increases ID for better flow or device delivery while maintaining moderate kink resistance.
0.0314"
0.798 mm
0.0053"
0.135 mm
183%
Compared to standard RW flow
1.05e-7
in⁴ (moment of inertia)
A wall of 0.0053" yields a nominal ID of 0.0314" and a 183% flow capacity relative to regular wall. Verify your internal guidewire size or device compatibility before finalizing.
Flow Rate vs. Wall Thickness (Poiseuille's Law): Shifting from a 19G Regular Wall (RW) to a Thin Wall (TW) increases relative flow efficiency by ~85%. TW (0.0053" wall) is the optimal starting point for fluid delivery applications without extreme loss of column strength.
Clearance Maximization (ISO 9626 Compliance): Extra Thin Wall (XTW) yields a 0.0343" (0.870 mm) ID, crucial for passing 0.032" and 0.033" sensor leads or inner catheters. However, it sacrifices ~30% of column stiffness compared to RW, requiring careful pushability analysis.
Kink Susceptibility & Trackability Trade-off: Decreasing wall thickness improves trackability through tortuous anatomy but drastically reduces torque response and pushability. Walls below 0.0039" (like UTW) are highly susceptible to buckling under bending stresses and often require structural compensation like spiral laser cutting or braided jackets.
Material Options for Thin Walls: While 304/304L stainless steel offers the best strength-to-cost ratio, 316L is preferred for enhanced corrosion resistance. For highly tortuous paths using XTW/UTW, Cobalt-Chrome or Nitinol are often necessary to restore kink resistance.
| Wall Category | OD (Nominal) | ID (Nominal) | Wall Thickness | Flow (vs. RW) | Primary Limitation |
|---|---|---|---|---|---|
| Regular Wall (RW) | 0.0420" / 1.067 mm | 0.0270" / 0.686 mm | 0.0075" / 0.191 mm | 100% (Baseline) | Limited lumen size |
| Thin Wall (TW) | 0.0420" / 1.067 mm | 0.0315" / 0.800 mm | 0.0053" / 0.133 mm | ~185% | Reduced column strength |
| Extra Thin Wall (XTW) | 0.0420" / 1.067 mm | 0.0343" / 0.870 mm | 0.0039" / 0.098 mm | ~260% | High kink risk |
| Ultra Thin Wall (UTW) | 0.0420" / 1.067 mm | 0.0362" / 0.920 mm | 0.0029" / 0.074 mm | ~320% | Requires reinforcement |
*Dimensions and flow percentages are theoretical nominals based on ISO 9626 gauge tables. Supplier-specific capabilities and tolerance stacks will vary. For TW, ISO 9626 specifies a minimum ID of 0.750 mm.
This tool is designed for early-stage engineering screening (published 2026-09-26; updated 2026-09-26). Calculations rely on nominal dimensions and ideal geometries.
According to ISO 9626, a standard 19 gauge (19G) hypotube has a nominal outer diameter of 1.067 mm (0.0420 inches). The standard allows an OD range of 1.030 mm to 1.100 mm.
A 19G Thin Wall (TW) tube typically has an ID of 0.0315" (0.800 mm) compared to the 0.0270" (0.686 mm) ID of a Regular Wall (RW) tube. By Poiseuille's Law, this ~16% increase in ID yields roughly an 85% increase in theoretical fluid flow rate.
XTW is specified when you need to maximize the lumen (e.g., ID 0.0343") for larger device passage or extreme fluid flow, and can compromise on column strength. However, XTW tubes (wall ~0.0039") are more susceptible to kinking during tight bends and typically require additional reinforcement, such as braiding or over-molding.
Yes, while 304/304L and 316L stainless steels are most common, Nitinol can also be drawn to 19G thinwall dimensions. Nitinol offers superelasticity which dramatically improves kink resistance, a critical benefit when wall thicknesses drop below 0.005".
Standard OD/ID tolerances are typically ±0.0005". In thin wall tubes (e.g., 0.0053" nominal wall), a worst-case tolerance stack can significantly affect the actual wall thickness and concentricity, potentially creating weak points. Always specify whether your critical dimensions are OD/ID or OD/Wall.
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