Water & Containers

Pipe Volume Calculator

Estimate the internal water volume of a pipe from internal diameter and length.

Units

Your measurements

Results update as you type.

Example shown — use your own measurements.

Actual inside diameter — nominal pipe names are not diameters.

Extra options & cost (optional)
Fractions and number formats

Use decimals (12.5), fractions (12 1/2 or 12-1/2), or explicit lengths (12ft 6in, 12′ 6″, 25 mm). A comma followed by one or two digits is a decimal comma: 12,5 = 12.5. Grouped commas mean thousands: 1,200 = 1200. Use a decimal point for ambiguous values. Scientific notation is not accepted.

Enter your measurements

Results update as you type.

About this calculator

Enter the internal diameter (not the nominal pipe size) and the length, with an optional quantity of identical sections. Capacity is shown in litres, cubic metres, US gallons, imperial gallons and cubic feet.

How to use this calculator

  1. Measure the pipe's internal diameter — check specifications if you only know the nominal size.
  2. Measure the total length.
  3. Set the quantity for identical sections.
  4. Calculate for capacity in all supported units.

Formula

Volume = π × (internal diameter ÷ 2)² × length × quantity

1 m³ = 1000 L exactly; 1 US gal = 231 in³; 1 imp gal = 4.54609 L

Assumptions

  • The internal diameter is used; nominal trade sizes are not diameters.
  • Cylindrical, straight-run geometry; fittings are ignored.
  • Quantities are exact cylinder volumes.

Common mistakes

  • Using outside or nominal diameter instead of internal bore.
  • Reading stored volume as a flow rate.
  • Forgetting separate fittings and tanks in a total system volume.

Worked example

Try it: press “Load example” above the form.

A 100 mm ID pipe of 10 m holds π × 0.05² × 10 = 78.54 L.

Limitations

No pressure, flow, structural or plumbing-code design. Internal capacity only.

Frequently asked questions

Do I enter inside or outside pipe diameter?

Use the internal bore diameter. Wall thickness and a nominal pipe label do not directly state the volume available for water. A supplier dimensional table can provide the actual bore.

Does pipe volume tell me the flow rate?

No. Volume is capacity. Flow also depends on time or on fluid velocity and cross-sectional area. Use the Flow Rate Calculator for those inputs.

What does the worked example show?

A 100 mm ID pipe of 10 m holds π × 0.05² × 10 = 78.54 L.

Which assumptions should I check before using the result?

No pressure, flow, structural or plumbing-code design. Internal capacity only.

Reviewed by Codex AI editorial agent (Editorial, 2026-11-12).

Sources

Sources explain the methods and any named product presets. Check your product label where coverage, yield or density differs.

Calculation documentation · Updated 2026-11-08 · Version 1.6.4. Estimates are planning aids. Confirm quantities, coverage and prices with your supplier before purchasing. Found an error? Report it.

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