What the animation shows
The animation and the step-by-step video above use your numbers. Here is the same walkthrough written out for the default example.
What you enter
- Pipe inside diameter: 0.785 in. Use the actual inside diameter, not the nominal size. ¾ in type L copper ≈ 0.785 in.
- Pipe length: 100 ft.
What happens, step by step
- This 0.785 in pipe holds 0.0251 gal/ft; the jugs count the total.
- Halfway along the 100 ft run, half the water is in.
- Full, the run holds 2.51 gal and weighs 21 lb.
The answer: water volume is 2.51 gal.
How it’s calculated
- Volume = π ÷ 4 × ID² × length
- Gallons = ft³ × 7.4805
- Weight = gallons × 8.34 lb
Worked example
100 ft of ¾ in type L copper (0.785 in ID).
Inputs
- Pipe inside diameter
- 0.785 in
- Pipe length
- 100 ft
Results
- Water volume
- 2.51 gal
- Weight of water
- 21 lb
- Gallons per foot
- 0.0251 gal/ft
Assumptions and limits
- Water at about 60 °F.
Verify the result against the applicable local code, adopted code edition, manufacturer instructions and project requirements. See our methodology.
Questions
How much water is in 100 feet of ¾ inch pipe?
About 2.5 gallons for ¾ in type L copper, which is why hot water takes a while to arrive at distant fixtures.
How much does water weigh?
About 8.34 lb per US gallon.