Pipe Volume Calculator

Every run of pipe holds water, and sometimes that number matters more than the pipe itself - for expansion tanks, flushing, antifreeze charges, or just knowing how much will spill when you cut it. The volume is a cylinder with the bore for its circle.

Pipe Volume Calculator serves up that volume in every unit you are ever asked for, and the weight of the water inside it.

• Cylinder math: Volume from bore and length.
• Every unit: Gallons, litres, cu ft, cu m.
• Water weight: kg and lbs ready for dead-load checks.
• Per 100 ft: Reference value for quick tables.
• Metric or imperial: Enter in either system.
• Export: Text, CSV or JSON report.

1. Enter the run length (feet or metres).
2. Enter the internal diameter (inches or mm).
3. Read the volume in the unit you need.
4. Check the weight for pipe hangers and structure.
5. Export the result for the record.

Example 1. 50 ft of 3/4 in (0.785 in bore) holds about 1.3 gallons - near 15 lbs of water.

Example 2. 100 m of 20 mm PEX holds about 31.4 litres.

Example 3. A 2 in main 100 ft long holds about 16 gallons.

• Goes with sizing: Volume answers follow diameter work.
• Universal output: No unit conversion hunting.
• Weight built in: Loads come for free.
• Field instant: No tables to keep.
• Free and private: No uploads, no logging.