Calculated result
26.1gal
Pipe volume
Formula
UTIL-PIPE-001gallons = π × (ID ÷ 2)² × length × 7.48052
3.491 ft³
Volume
98.8 L
Litres
Utilities calculator
Pipe volume calculator
40 ft of 4 in inside-diameter pipe holds about 26.1 gallons. In metric, volume is 0.1 m³.
Formula. gallons = π × (ID ÷ 2)² × length × 7.48052
Pipe gallons and cubic feet from inside diameter and length. Not a flow or plumbing-code design.
By Feroz Sheikh · Formula UTIL-PIPE-001 v1.0.0 · Tested formula
Formula
UTIL-PIPE-001v1.0.0Project inputs
Enter your measurements. Switching units converts the same project, including coverage and unit rates. Package yields keep the unit printed beside each field.
Refine measurements and rates at any time. Your current values are included in the material-list PDF.
Planning estimate, not engineering advice. Confirm site measurements and product specifications. Calculation limits.
Volume is π × (inside diameter ÷ 2)² × length. Gallons use 7.48052 US gallons per cubic foot.
- Use inside diameter, not the nominal trade size if they differ.
- Length is the pipe, not the trench.
- This is capacity, not flow.
Add your project costs
Add rates if you are pricing a related project line. Pick a currency — badges, inputs, and totals follow.
This page is geometry, not a material takeoff. Leave rates at zero unless you are pricing a related line. Construclytic does not fetch supplier prices.
How this calculator works
A transparent pipe volume takeoff.
Feroz SheikhWritten and reviewed by Feroz Sheikh · founder
Volume is π × (inside diameter ÷ 2)² × length. Gallons use 7.48052 US gallons per cubic foot.
UTIL-PIPE-001 is capacity: π × (inside diameter ÷ 2)² × length, in US gallons at 7.48052 gal/ft³. It is not flow, friction, fixture units or a plumbing-code path. Use inside diameter, not the nominal trade size when they differ.
Worked example. Example: 40 ft of 4 in inside-diameter pipe holds about 26.1 gallons.
See the example inputs and calculated result
This separate example uses the calculator's starting values in imperial units. It stays unchanged when you edit the tool above. Example rates, yields and dimensions are assumptions, not recommendations for your project.
| Input | Example value |
|---|---|
| Inside diameter | 4 in |
| Pipe length | 40 ft |
Example result: Pipe volume — 26.1 gal.
gallons = π × (ID ÷ 2)² × length × 7.48052
Use the labelled units above when reproducing this example. To work in metric, switch the calculator to Metric; applicable measurements are converted, while product-specific units remain labelled.
- 1. Use inside diameter, not the nominal trade size if they differ.
- 2. Length is the pipe, not the trench.
- 3. This is capacity, not flow.
Field notes that change the number
- Enter inside diameter. Schedule 40 and 80 do not share an ID on the same trade size.
- Length is the pipe, not the trench.
- This is capacity, not GPM.
Common mistakes
- Using nominal trade size as inside diameter on a tight fill.
- Calling this a flow or fixture-unit calculation.
- Using trench length as pipe length when the run snakes.
Need the broader workflow? Read the utilities planning guide.
How-to: Trench excavation volume: in-place geometry versus loose haulage · Pipe internal volume in litres: use inside diameter, not trade size
Questions
Questions about pipe volume
Schedule 40 or 80?
Wall thickness changes inside diameter. Enter the ID, not the trade size, when it matters.
Is this a flow calculation?
No. Friction, fixture units and code sizing stay with the plumber.
What is the formula ID?
This pipe volume calculator publishes formula UTIL-PIPE-001, version 1.0.0. The ID stays on the result and on the estimate line.