Enter a pipe's inside diameter and length to calculate its volume in gallons, cubic feet, and liters.
How to Use the Pipe Volume Calculator
Enter the pipe's inside diameter and its length; the result is the volume of fluid the pipe actually holds, shown in gallons, cubic feet, and liters at once.
volume = π × (inside diameter ÷ 2)² × length"Inside diameter" is doing real work in that sentence — a pipe labeled 4 inches nominally doesn't hold water in a 4-inch-diameter column, since wall thickness eats into the usable bore. Schedule 40 PVC, copper, and steel pipe all shave a different amount off nominal size, so for anything beyond a rough estimate, check the pipe's actual measured or spec-sheet inside diameter rather than the number printed on the label.
This kind of figure comes up more than it might seem: draining a line before cutting into it, purging air from a newly filled loop, dosing a chemical treatment proportional to system volume, or estimating how much water a home's plumbing run holds between the meter and the tap.