Standard 1" SDR-9 PEX tubing has an inner diameter of 0.863 inches, holding 0.0304 US gallons (0.377 liters per meter) per linear foot. Part of our universal Pipe Volume Calculator and Water Pipe Volume tools.
Calculations are based on cylindrical formula \(V = \pi r^2 L\). Verify dimensions against manufacturer specs for code submittals.
Instant capacity and weight lookup table for common PEX coil lengths and radiant floor heating loops.
| Coil Length (Ft) | US Gallons | Liters | Cubic Feet (ft³) | Water Weight (lbs) | Dry Tubing (lbs) | Total Wet Weight |
|---|---|---|---|---|---|---|
| 1 ft | 0.030 gal | 0.11 L | 0.004 ft³ | 0.3 lbs | 0.2 lbs | 0.4 lbs |
| 5 ft | 0.152 gal | 0.57 L | 0.020 ft³ | 1.3 lbs | 0.8 lbs | 2.1 lbs |
| 10 ft | 0.304 gal | 1.15 L | 0.041 ft³ | 2.5 lbs | 1.7 lbs | 4.2 lbs |
| 25 ft | 0.760 gal | 2.87 L | 0.102 ft³ | 6.3 lbs | 4.2 lbs | 10.6 lbs |
| 50 ft | 1.52 gal | 5.7 L | 0.20 ft³ | 12.7 lbs | 8.5 lbs | 21.1 lbs |
| 100 ft | 3.04 gal | 11.5 L | 0.41 ft³ | 25.4 lbs | 16.9 lbs | 42.3 lbs |
| 200 ft | 6.08 gal | 23.0 L | 0.81 ft³ | 50.8 lbs | 33.8 lbs | 84.6 lbs |
| 300 ft | 9.12 gal | 34.5 L | 1.22 ft³ | 76.2 lbs | 50.7 lbs | 126.9 lbs |
| 500 ft | 15.20 gal | 57.5 L | 2.03 ft³ | 127.0 lbs | 84.5 lbs | 211.5 lbs |
| 1000 ft | 30.40 gal | 114.9 L | 4.06 ft³ | 254.0 lbs | 169.0 lbs | 423.0 lbs |
Step-by-step mathematical demonstration using cylinder geometric principles and SDR-9 ASTM specifications.
Nominal size is 1", but true inner diameter is 0.863 inches.
r = ID / 2 = 0.863 / 2 = 0.4315" Compute circular cross-section area using $A = \pi \times r^2$:
A = \pi \times (0.4315)^2 = 0.5849 sq in Multiply cross-sectional area by 12 inches (1 linear foot):
V_linear = 0.5849 \times 12 = 7.019 cu in/ft Divide cubic inches by 231 (cubic inches in 1 US Gallon):
Gallons/Ft = 7.019 / 231 = 0.0304 Gal/Ft Physical dimensions, pressure thresholds, and hydraulic velocity limits.
Primary Use Case: Standard for whole-house main water service from meter to manifold and commercial boiler primary distribution headers.
Explore adjacent diameter calculations or compare with PVC & Copper piping.
Frequently asked engineering and volumetric capacity questions for 1" PEX.
A 100-foot run of 1-inch PEX tubing holds 3.04 US Gallons (11.51 Liters) of water.