Pipe Volume Calculator
Free pipe volume calculator. Enter inner diameter and length to get the water volume in gallons per foot, total gallons, litres and water weight for any pipe.
Use the INNER diameter (not the nominal or outer size) for an accurate capacity — e.g. 4" Schedule 40 PVC has a 4.03" inner diameter.
About This Free Online Pipe Volume Calculator
Our free pipe volume calculator tells you how much water (or any liquid) a length of pipe holds. Enter the inner diameter in inches and the pipe length in feet, and the tool returns the volume per foot in gallons, the total gallons, the equivalent in litres, and the weight of the water inside — useful for sizing pumps, drains, hydronic loops and irrigation runs. Use the INNER diameter for accurate capacity. Every calculation runs instantly in your browser with no signup.
Features of Our Pipe Volume Calculator
- Gallons per foot, total gallons, litres and water weight
- Uses the inner diameter for true capacity
- Works for copper, PEX, PVC, black iron and ductile pipe
- Great for hydronic loops, irrigation, drains and wells
- Water weight helps size supports and pump lifts
- 100% client-side and private — no signup, no data sent
How to Use the Pipe Volume Calculator
Using this tool is simple and requires no signup or registration. Follow these steps:
- Enter the INNER diameter of the pipe in inches (e.g. 0.622 for 3/4" L copper).
- Enter the total pipe length in feet.
- Read the gallons per foot and the total volume.
- Use the water weight to check pump or support sizing.
Frequently Asked Questions About Pipe Volume Calculator
How do you calculate the volume of a pipe?
Pipe volume is the circular area of the inside (π × radius²) multiplied by the length. This calculator computes the area from the inner diameter, gives the volume per foot, then multiplies by the total length for gallons, litres and water weight.
Should I use the inner or outer diameter?
Use the INNER diameter. The outer diameter includes the pipe wall, which would overstate capacity. Pipe schedules (like Schedule 40) have a known inner diameter for each nominal size — look that up for a precise figure.
How much water does a 4 inch pipe hold per foot?
A pipe with a 4 inch inner diameter holds about 0.65 gallons per linear foot (roughly 5.2 gallons per 8 ft section). Enter your exact inner diameter for a precise per-foot figure.
Why does water weight matter?
A full pipe adds real load. Water weighs about 8.34 lb per gallon, so a long horizontal run or riser can weigh hundreds of pounds — important for hanger spacing, pump head and shipping.
Is this pipe volume calculator free?
Yes, completely free with no signup. Every calculation runs in your browser, so nothing is uploaded or tracked.
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