🌊 Fluid Mechanics

Pipe Volume Calculator

Calculate the volume of water or liquid inside any pipe. Enter the inner diameter and length to get volume in gallons, liters, cubic feet, and cubic inches.

🔧 Pipe Volume Calculator
in
ft
Pipe Volume
—

📋 Volume of Water in Common Pipe Sizes

Volume per foot of pipe length for standard nominal pipe sizes:

Nominal Size Inner Dia. (in) Gal/ft Gal/100ft
½"0.6220.0161.6
¾"0.8240.0282.8
1"1.0490.0454.5
1¼"1.3800.0787.8
1½"1.6100.10610.6
2"2.0670.17417.4
3"3.0680.38438.4
4"4.0260.66166.1
6"6.0651.501150.1
8"7.9812.599259.9

📖 How to Calculate Pipe Volume

The volume of a pipe is calculated using the cylinder volume formula, using the pipe's inner diameter (not outer diameter).

V = π × r² × L
Where r = inner radius, L = length. For gallons: divide cubic inches by 231

Step-by-Step

  1. Find inner diameter. Use the pipe's inner diameter (ID), not the outer diameter (OD). Nominal pipe size differs from actual inner diameter.
  2. Calculate radius. Divide diameter by 2.
  3. Calculate cross-sectional area. π × r² gives the circular area.
  4. Multiply by length. Area × length gives volume in cubic units.
  5. Convert units. Divide cubic inches by 231 for US gallons, or by 1728 for cubic feet.