Pipe Volume Calculator
ID × length → gallons in the line. Click any i for detail.
Pipe
Inside diameter (in)
i
ID
Inside diameter, not nominal pipe size. Schedule 40 2-inch is not exactly 2 in ID. |
|
|---|---|
Length (ft)
i
Length
One run of pipe in feet. |
|
Number of runs
i
Count
Identical pipes. Different IDs need separate calculations. |
How to use this calculator
- Enter inside diameter in inches.
- Enter length in feet.
- Set how many identical runs.
- Read total gallons and gallons per foot.
Results explained
Radius in feet = ID ÷ 24. Volume = π r² × length × count, then × 7.48052 for gallons.
Quick reference: pipe volume
Always use ID. Nominal size is a name, not a measurement.
| Item | Detail |
|---|---|
| 2 in ID × 100 ft | See result |
| 1 ft³ | ≈ 7.48 gal |
| Tank instead? | Tank volume calculator |
| Flow / drop | Voltage drop is electrical — not this |
Fittings add a little volume; this is straight pipe.
How the estimate is built
gal = π (ID/24)² × length_ft × 7.48052 × count.
Example scenario
2 in ID, 100 ft, one run → about 16.3 gallons.
FAQ
Nominal 2-inch PVC?
Look up the ID for that schedule; don’t type 2 blindly.
Metric mm?
Convert ID to inches, length to feet.
Partially full?
This is 100% full bore.