Exhaust Tubing Size Chart: OD, Wall Thickness, and ID
Every tube size we stock in one place: outside diameter, gauge, wall thickness, and inside diameter
When you're planning an exhaust, turbo, or intercooler build, the numbers that matter are the tube's outside diameter (OD), its wall thickness, and the inside diameter (ID) that leaves you with. This chart lists every straight tube size we carry, by alloy, so you can match parts and compare options quickly.
A note on choosing a diameter: the right tube size for a build depends on the engine, power level, vehicle, and goals. That decision belongs with an experienced builder or fabricator who knows your setup, so this chart is reference data only, not a sizing recommendation.
Material tolerances: All dimensions listed are nominal. Tube OD and wall thickness are subject to standard mill tolerances, so actual measurements can vary slightly from the values shown. ID values are calculated from nominal OD and wall and will vary with them. Check each product page for its specifications before ordering.
How Tube Is Measured
- Outside diameter (OD): Tube is sized by its OD. A 3.000" tube measures 3.000" across the outside.
- Wall thickness: Listed by gauge or decimal inches (titanium is usually listed in millimeters). A higher gauge number means a thinner wall.
- Inside diameter (ID): ID = OD − (2 × wall). A 3.000" OD tube with a 0.065" wall has a 2.870" ID.
To measure tube you already have, use calipers across the outside for OD and on the cut end for wall thickness, then calculate the ID.
Gauge Reference
| Gauge | Stainless Wall | Aluminum Wall |
|---|---|---|
| 18ga | 0.049" | — |
| 16ga | 0.065" | 0.065" |
| 14ga | 0.083" | 0.079" |
| 12ga | 0.109" | — |
Wall thicknesses as listed on our tube products. Nominal dimensions; tolerances apply.
Tube vs. Pipe
"Exhaust pipe" is usually tube, not pipe. Tube is sized by its actual OD. Pipe is sized by a nominal pipe size (NPS) that doesn't match its actual OD: 2" NPS pipe measures 2.375" OD, and 2-1/2" NPS measures 2.875" OD. If you're working with turbo manifold pipe and weld fittings, see Pipe Size vs. Tube Size and What Is Nominal Pipe Size (NPS)?
304 Stainless Tube
Our most popular exhaust and intercooler tube. Brushed finish, 2-foot and 4-foot lengths. Shop 304 stainless tube
| OD | Gauge | Wall | ID | Lengths |
|---|---|---|---|---|
| 1.500" | 16ga | 0.065" | 1.370" | 2 / 4 ft |
| 1.625" | 16ga | 0.065" | 1.495" | 2 ft |
| 1.750" | 16ga | 0.065" | 1.620" | 2 / 4 ft |
| 2.000" | 16ga | 0.065" | 1.870" | 2 / 4 ft |
| 2.250" | 16ga | 0.065" | 2.120" | 2 / 4 ft |
| 2.375" | 16ga | 0.065" | 2.245" | 2 ft |
| 2.500" | 16ga | 0.065" | 2.370" | 2 / 4 ft |
| 3.000" | 16ga | 0.065" | 2.870" | 2 / 4 ft |
| 3.500" | 16ga | 0.065" | 3.370" | 2 ft |
| 3.500" | 14ga | 0.083" | 3.334" | 4 ft |
| 4.000" | 16ga | 0.065" | 3.870" | 2 ft |
| 4.000" | 14ga | 0.083" | 3.834" | 4 ft |
| 4.500" | 14ga | 0.083" | 4.334" | 4 ft |
| 5.000" | 16ga | 0.065" | 4.870" | 2 ft |
| 5.000" | 14ga | 0.083" | 4.834" | 4 ft |
| 6.000" | 14ga | 0.083" | 5.834" | 4 ft |
Nominal dimensions; material tolerances apply.
321 Stainless Tube
Titanium-stabilized for sustained heat and heat cycling on turbo manifolds and headers. 4-foot lengths. Shop 321 stainless tube
| OD | Gauge | Wall | ID | Lengths |
|---|---|---|---|---|
| 1.500" | 18ga | 0.049" | 1.402" | 4 ft |
| 1.625" | 16ga | 0.065" | 1.495" | 4 ft |
| 1.750" | 18ga | 0.049" | 1.652" | 4 ft |
| 2.250" | 16ga | 0.065" | 2.120" | 4 ft |
| 2.500" | 16ga | 0.065" | 2.370" | 4 ft |
| 3.000" | 16ga | 0.065" | 2.870" | 4 ft |
Nominal dimensions; material tolerances apply.
316L Stainless Tube
For marine exhaust, saltwater exposure, and sanitary systems. Polished OD and ID, 4-foot lengths. Shop 316L stainless tube
| OD | Gauge | Wall | ID | Lengths |
|---|---|---|---|---|
| 0.500" | 16ga | 0.065" | 0.370" | 4 ft |
| 0.750" | 16ga | 0.065" | 0.620" | 4 ft |
| 1.000" | 16ga | 0.065" | 0.870" | 4 ft |
| 1.250" | 16ga | 0.065" | 1.120" | 4 ft |
| 1.500" | 16ga | 0.065" | 1.370" | 4 ft |
| 2.000" | 16ga | 0.065" | 1.870" | 4 ft |
| 2.500" | 16ga | 0.065" | 2.370" | 4 ft |
| 3.000" | 16ga | 0.065" | 2.870" | 4 ft |
| 4.000" | 14ga | 0.083" | 3.834" | 4 ft |
| 6.000" | 14ga | 0.083" | 5.834" | 4 ft |
| 6.000" | 12ga | 0.109" | 5.782" | 4 ft |
Nominal dimensions; material tolerances apply.
6061-T6 Aluminum Tube
For intercooler, charge, and intake piping. Polished OD, 2-foot lengths. Shop 6061 aluminum tube
| OD | Gauge | Wall | ID | Lengths |
|---|---|---|---|---|
| 1.250" | 16ga | 0.065" | 1.120" | 2 ft |
| 1.500" | 16ga | 0.065" | 1.370" | 2 ft |
| 1.750" | 16ga | 0.065" | 1.620" | 2 ft |
| 2.000" | 16ga | 0.065" | 1.870" | 2 ft |
| 2.250" | 16ga | 0.065" | 2.120" | 2 ft |
| 2.500" | 16ga | 0.065" | 2.370" | 2 ft |
| 3.000" | 16ga | 0.065" | 2.870" | 2 ft |
| 3.500" | 14ga | 0.079" | 3.342" | 2 ft |
| 4.000" | 14ga | 0.079" | 3.842" | 2 ft |
| 5.000" | 14ga | — | — | 2 ft |
Nominal dimensions; material tolerances apply.
CP1 Titanium Tube
Thin-wall tube for weight-critical exhaust. 0.039" (1mm) and 0.047" (1.2mm) walls, 2-foot and 4-foot lengths. Shop titanium tube
| OD | Gauge | Wall | ID | Lengths |
|---|---|---|---|---|
| 1.500" | 1mm | 0.039" | 1.422" | 2 ft |
| 1.750" | 1.2mm | 0.047" | 1.656" | 2 ft |
| 2.000" | 1mm | 0.039" | 1.922" | 2 ft |
| 2.000" | 1.2mm | 0.047" | 1.906" | 2 ft |
| 2.250" | 1mm | 0.039" | 2.172" | 2 ft |
| 2.250" | 1.2mm | 0.047" | 2.156" | 2 ft |
| 2.375" | 1mm | 0.039" | 2.297" | 2 ft |
| 2.500" | 1mm | 0.039" | 2.422" | 2 / 4 ft |
| 2.500" | 1.2mm | 0.047" | 2.406" | 2 / 4 ft |
| 3.000" | 1mm | 0.039" | 2.922" | 2 / 4 ft |
| 3.000" | 1.2mm | 0.047" | 2.906" | 2 / 4 ft |
| 3.500" | 1mm | 0.039" | 3.422" | 2 / 4 ft |
| 3.500" | 1.2mm | 0.047" | 3.406" | 2 / 4 ft |
| 4.000" | 1mm | 0.039" | 3.922" | 2 / 4 ft |
| 4.000" | 1.2mm | 0.047" | 3.906" | 2 / 4 ft |
| 5.000" | 1mm | 0.039" | 4.922" | 2 / 4 ft |
| 5.000" | 1.2mm | 0.047" | 4.906" | 2 / 4 ft |
ID values are calculated from OD and wall thickness. Nominal dimensions; material tolerances apply. Check each product page for its dimensional drawing and specifications.
Matching Parts to Your Tube
Mandrel bends, V-band clamps and flanges, reducers, and couplers are all sized to the tube OD, so once you know your OD you can match everything else to it. See our Mandrel Bend Selection Guide for bends and our V-Band Clamp and Flange guide for connections.
Questions about a specific size or alloy? Email us at sales@aceraceparts.com.
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