Pipe Volume Calculator
Calculate the water volume contained in any length and diameter of pipe.
Results
Visualization
How It Works
Pipe volume is calculated from the cross-sectional area and length. Knowing the water volume is essential for antifreeze calculations, system draining, purging air, and estimating water age in dead-end mains.
The Formula
V = pi x r^2 x L (then convert ft3 to gallons: x 7.48052)
Variables
- V — Volume in cubic feet
- r — Inside radius in feet
- L — Pipe length in feet
Worked Example
A 100 ft run of 3/4" pipe: r = 0.03125 ft, V = pi x 0.03125^2 x 100 = 0.3068 ft3 = 2.30 gallons.
Practical Tips
- 1 gallon of water weighs 8.34 lbs
- Antifreeze calculations need total system volume
- Water in pipes can freeze and burst if not drained
- Volume quadruples when diameter doubles