Pipe Volume Calculator: Here's How to Find the Volume of a Pipe

Repairwoman inspecting pipes
Photo: SolStock/ Getty Images
Repairwoman inspecting pipes
Photo: SolStock/ Getty Images
Deane Biermeier
Written by Deane Biermeier
Contributing Writer
Updated Jun 11, 2025
Highlights

  • To accurately calculate the volume of a pipe, you need to know the precise inner diameter of the pipe.

  • Pipe volume is a handy measurement for calculating flow rates in plumbing systems. 

  • Most residential plumbing and HVAC systems use standard pipe sizes.

Get quotes from up to 3 pros!
Enter a zip below and get matched to top-rated pros near you.
Geo Icon

Because most pipes are cylindrical, knowing how to find the volume of a pipe is as simple as measuring the diameter and length and plugging those values into a formula. However, for fittings and elbows, additional measurements are necessary. This calculator will help you determine the pipe volume for plumbing systems in your home.

Read more

How Much Pipe Volume Is Needed For Plumbing 

Most household plumbing pipes, such as supply lines, sink drains, or toilet drainpipes, come in standard sizes. This simplifies choosing the correct size for various applications and pipe replacements. The chart below shows the volume in cubic feet for one foot of various sizes of Schedule 40 PVC pipe.

Nominal Pipe Size (diameter, in inches)Pipe Volume (cubic feet per linear foot)
1/20.002
3/40.004
1.50.014
20.023
30.051
40.088
Read more

How to Calculate Pipe Volume

Part of becoming a licensed plumber is learning how to calculate and work with all sorts of pipe materials and the volume, or capacity, of those components.

To calculate the volume of any pipe, measure the inside diameter of the pipe in inches. Divide it by two to get the radius. Square the radius by multiplying it by itself. Now multiply the result by pi (3.14). Multiply that result by the pipe's length in inches to get the volume in cubic inches. Divide the volume in cubic inches by 1728 to determine the volume in cubic feet. 

Pipe Volume (cubic feet) = Radius squared x 3.14 x Length / 1728

How to Measure Pipe Volume

Plumber working on pipes in the kitchen
Photo:Paul Bradbury/KOTO/Adobe Stock

If you're trying to determine the volume of a pipe for which you can't access the inner diameter, such as when planning to replace a main water line that's active, you'll need to take a different approach. 

Measure the circumference of the pipe in question and calculate the inner diameter as closely as possible by dividing the circumference by pi, or 3.14. Now you can use the diameter figure to complete your calculations. 

How to Measure Straight Pipe Volume

When you measure the length of pipe you're calculating for, the simplest method is to measure in feet and divide the total by 12, and work your calculations in inches. 

How to Measure Pipe Fitting Volume

To measure the volume of pipe fittings, such as tees and wyes, treat each section of the fitting as its own calculation. Add the values of the parts to obtain the total fitting volume. For reducing fittings, average the large and small diameters for the diameter value.

Read more

Who to Hire to Calculate Pipe Volume

Calculating pipe volume is essential for installing or repairing the plumbing in your home as a DIY project. However, most homeowners leave this sort of work to the pros. A local plumbing company will have detailed knowledge of the municipal water system in your location, resulting in more accurate calculations based on your needs. 

Read more
Frequently Asked Questions

A plumbing pipe is simply a container for water, sewage, or even air in some cases. Like any other type of container, it has an internal empty space, or capacity. That space is the amount of room a plumbing component has to hold liquid. That amount of room is the volume.

Having the right size pipe ensures proper drainage and helps protect against clogs and other plumbing problems. A pipe that's too small will take longer to drain, which can result in backups. And solids can build up in pipes that are too large. Choosing a pipe with the appropriate volume also means it will be able to handle water pressure, which is the force behind the water.

Need professional help with your project?
Get quotes from top-rated pros.
Learn more about our contributor
Deane Biermeier
Written by Deane Biermeier
Contributing Writer
Deane has spent 30+ years in residential construction, contracting, remodeling, maintenance, and home repair, and now contributes DIY and educational articles for publications like Forbes Home and U.S. News. Throughout his career, he has strived to help homeowners find the potential hidden within the walls of every home and empower them to take control of their household repair and remodeling endeavors.

The homeowners guide to plumbing services

From average costs to expert advice, get all the answers you need to get your job done.

See all articles