3 December 2025 · 10 min
Selecting the correct PTFE tube size is critical for ensuring proper fit, achieving required flow rates, and maintaining system performance. This guide covers the key dimensional parameters, standard size ranges, wall thickness categories, and the application-specific size ranges most frequently specified across industries.
Understanding PTFE Tube Dimensions
Three measurements define a PTFE tube. Inside Diameter (ID) is the internal measurement controlling flow capacity and component compatibility. Outside Diameter (OD) determines fitting compatibility and space requirements. Wall Thickness (WT) is calculated as (OD – ID) ÷ 2, and directly governs pressure rating and flexibility. Always specify which dimension is critical for your fitting system: OD for compression fittings, ID for bore flow calculations.
Wall Thickness Categories
| Category | Wall Thickness | Typical Applications |
|---|---|---|
| Thin Wall | 0.15–0.5mm | Medical devices, wire insulation, miniature instruments |
| Standard Wall | 0.5–1.5mm | Laboratory equipment, analytical instruments, chemical transfer |
| Heavy Wall | 1.5–3.0mm+ | High-pressure hydraulics, mechanical components, bushings |
Standard Metric Size Reference
| OD (mm) | ID (mm) | Wall (mm) | OD Tolerance |
|---|---|---|---|
| 1.0 | 0.5 | 0.25 | ±0.05 |
| 2.0 | 1.0 | 0.50 | ±0.08 |
| 3.0 | 2.0 | 0.50 | ±0.08 |
| 4.0 | 3.0 | 0.50 | ±0.10 |
| 6.0 | 4.0 | 1.00 | ±0.10 |
| 8.0 | 6.0 | 1.00 | ±0.12 |
| 10.0 | 8.0 | 1.00 | ±0.15 |
| 12.0 | 10.0 | 1.00 | ±0.15 |
| 16.0 | 13.0 | 1.50 | ±0.20 |
| 20.0 | 17.0 | 1.50 | ±0.20 |
| 25.0 | 22.0 | 1.50 | ±0.25 |
Application Size Guidelines
| Industry / Application | Typical ID Range |
|---|---|
| Laboratory and analytical equipment | 0.5–4mm ID |
| Medical devices | 0.3–6mm ID |
| Pharmaceutical fluid transfer | 4–16mm ID |
| Chemical processing | 4–25mm ID |
| Automotive and aerospace | 3–12mm ID |
| Wire and cable insulation | By wire gauge (AWG/SWG) |
Ordering Tip
For compression fittings: specify OD as critical, allow ID to float within standard tolerance. For bore-flow applications: specify ID as critical, allow OD to float. For pressure-critical applications: specify both dimensions with an understanding that one will be held to tighter tolerance than the other.