Pipe Volume Calculator
Calculate the volume of liquid inside a pipe.
How It Works
Volume = π × (Diameter ÷ 2 ÷ 12)² × Length. Gallons = Volume × 7.48052. Liters = Volume × 28.3168.
Example
A 3/4 in pipe 20 ft long holds about 0.46 gallons.
Frequently Asked Questions
Why compute pipe volume?
Useful for purging, chemical dosing, and estimating water held in long supply runs.
Is this inside diameter?
Enter the inner diameter for accurate volume; nominal pipe sizes have a smaller inside diameter.
How many gallons per 100 ft of pipe?
3/4 in holds ~2.3 gal/100 ft, 1 in ~4.1 gal/100 ft, 2 in ~16 gal/100 ft.