Pipe Volume Calculator
Find the exact volume of any pipe and the weight of the liquid it contains. Enter pipe diameter, length, and select the fluid type to get volume in gallons, liters, or cubic feet along with liquid weight.
Inside diameter of the pipe
Only used when "Custom Density" is selected
Where:
r = Inner Diameter ÷ 2 (radius in feet)
L = Pipe Length (feet)
Volume (gal) = Volume (ft³) × 7.48052
Volume (L) = Volume (m³) × 1000
Liquid Weight = Volume × Liquid Density
How do I calculate the volume of a pipe?
Pipe volume is calculated using the formula V = πr²h, where r is the inner radius and h is the pipe length. First find the radius by dividing the inner diameter by 2, then square it, multiply by π, then multiply by the length. Convert from cubic inches to gallons (divide by 231) or liters (multiply cubic meters by 1000).
Why use inner diameter instead of outer diameter?
The inner diameter (ID) represents the actual hollow space inside the pipe where fluid flows. The outer diameter (OD) includes the pipe wall thickness. Using OD would overestimate the volume. If you only know the pipe's OD, subtract twice the wall thickness to get the ID.
How much water does a 100-foot pipe hold?
A 4-inch diameter pipe that is 100 feet long holds approximately 65.5 gallons of water. A 6-inch pipe of the same length holds about 147 gallons. Flow rate also depends on pressure, friction, and pipe material — this calculator gives you the static volume capacity.
Does the pipe material affect the liquid weight?
No, pipe material does not affect the weight of the liquid inside — that depends only on the liquid density. However, the total weight of a full pipe system includes both the pipe material weight and the liquid weight. Use our Pipe Weight Calculator for the pipe itself.
🔗 Related Calculators
📐 Formula
Where:
r = Inner Diameter ÷ 2 (radius in feet)
L = Pipe Length (feet)
Volume (gal) = Volume (ft³) × 7.48052
Volume (L) = Volume (m³) × 1000
Liquid Weight = Volume × Liquid Density