Pipe Volume Calculator

Enter the length and diameter of your pipe in inches, and our calculator will determine the pipe volume in cubic inches, gallons, and pounds.

Pipe Volume Calculator

Enter the inner diameter and length of the pipe to calculate the volume:

  • liters
  • cubic inches
  • gallons
  • pounds

Pipe Volume Calculator
To calculate pipe volume in cubic inches, you’ll need the diameter and length of the pipe in inches. Here is the pipe volume formula:

Pipe Volume = π x (diameter²/4) x length in inches

Once you’ve determined the cubic inches of the pipe, you can convert them to gallons with the following formula:

Gallons = cubic inches ÷ 231

If you’d like to know the liquid density in pounds, multiply your cubic inches by 0.036.

Pounds = cubic inches x 0.036

Refer to our chart below for the pounds, cubic inches, and gallons of water per foot of pipe.

Pipe SizeVolume (in³/ft)Volume (gallons/ft)Weight (lb/ft)
1/16"0.0368 in³0.000159 gal0.001331 lbs
1/2"2.356 in³0.0102 gal0.0852 lbs
3/4"5.301 in³0.0229 gal0.1916 lbs
1"9.425 in³0.0408 gal0.3407 lbs
1 1/4"14.726 in³0.0637 gal0.5323 lbs
1 1/2"21.206 in³0.0918 gal0.7665 lbs
2"37.699 in³0.1632 gal1.363 lbs
2 1/2"58.905 in³0.255 gal2.129 lbs
3"84.823 in³0.3672 gal3.066 lbs
3 1/2"117.215 in³0.5076 gal4.236 lbs
4"150.8 in³0.6528 gal5.451 lbs
5"235.62 in³1.02 gal8.517 lbs
6"339.29 in³1.469 gal12.264 lbs

Calculating Pipe Volume: Example

If you’d like to know how to calculate pipe volume manually, we’ll review an example. 

Example: Your pipe’s dimensions are 2 inches in diameter and 25 feet long. 

The first step is to convert the length to inches. Since there are 12 inches in a foot, we’ll multiply 25 x 12 to determine the length in inches. 

25 x 12 = 300 inches

From there, we can plug numbers into our pipe volume formula. We will use 3.1415 for π. Our formula will look like this:

  • Pipe Volume = 3.1415 x (2²/4) x 600

Now we can solve the equation

  • Pipe Volume = 3.1415 x 1 x 600
  • Pipe Volume = 1,884.90 cubic inches

We can convert cubic inches to gallons by dividing by 231:

  • 8.16 Gallons = 1,884.90 ÷ 231

We can determine the liquid density of the pipe in pounds by multiplying cubic inches by 0.036:

  • 67.86 lbs. = 1,884.90 x 0.036

How Do I Calculate How Many Liters of Water a Pipe Will Hold?

If you’re looking to calculate how many liters of water a pipe will hold, start by using our equation to determine the pipe volume in cubic inches.

Pipe Volume = π x (diameter²/4) x length in inches

Then convert cubic inches to liters by dividing by 61.0237.

Liters of water a pipe can hold = cubic inches ÷ 61.0237

Frequently Asked Questions (FAQ)FAQ

What does pipe volume mean?

Pipe volume is the amount of substance a pipe can hold. Plumbers use pipe volume in building plans to ensure that a pipe is the correct size for a substance (like water or gas) to move through.

How to determine the diameter of a pipe?

If the end of the pipe is accessible, find the diameter by using a ruler or tape measure to measure the opening. If the pipe end is not accessible, you can use a flexible tape measure to measure the outer circumference and divide that number by pi, which is 3.1415.

How to determine the radius of a pipe?

The radius of a pipe is its diameter divided by 2.