Why use inside diameter?
Internal capacity is set by the open bore; wall thickness changes it.
MAXScanner calculator
Pipe Volume Calculator — Internal Capacity in Liters & Gallons
Calculate full internal pipe capacity from actual inside diameter, length and pipe count, with liters, cubic meters and US gallons.
Result
3.707 L
0.003707 m³ · 0.979 US gal
Uses actual inside diameter for 1 pipe(s).
Formula and worked example
V=π×(inside diameter/2)²×length×count.
A 2 in inside-diameter pipe 6 ft long holds about 0.98 US gal when completely full.
Assumptions
- Use actual inside diameter, not nominal pipe size or outside diameter.
- Straight circular pipes are assumed completely full.
Last updated: 2026-09-16
Frequently asked questions
Does this calculate flow rate?
No. Capacity is volume; flow also needs velocity or time.