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Circular Pipe Internal Capacity & Liquid Mass

Calculate the internal volume of a uniform circular pipe and the mass of a filling liquid using its density.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A 2 cm internal diameter over 10 m holds π liters, about 3.14159 L. At density 1,000 kg/m³, the liquid mass is about 3.14159 kg.

Volume = π × (inner diameter / 2)² × length; liquid mass = density × volume

Worked example

Enter these known values and leave the other values blank.

Internal diameter
2 cm
Pipe length
1000 cm
Liquid density
1000 kg/m³
Mass of filling liquid
3.14 kg
Internal liquid capacity
3.142 L

Assumptions and limitations

  • The model is a straight or measured-centerline pipe with a uniform circular bore. Use internal diameter, not nominal pipe size or outer diameter.
  • Diameter, length, density, volume and liquid mass must be positive. Fittings, valves and partial filling require separate volume adjustments.
  • The retained density default is 997 kg/m³, an approximate water value. Enter density appropriate to the fluid, temperature and pressure.
  • Liquid mass excludes the pipe material. Bookify uses 64-digit π rather than the source’s four-decimal approximation.
  • Arithmetic uses 64 significant decimal digits. Displayed results use the configured rounding.

Common questions

Do I enter the outer or inner diameter?

Enter the actual internal bore diameter. Outer diameter includes the pipe wall and overstates the space available for liquid.

References

Bookify replaces the rounded 3.1415 volume constant and its derived inverse coefficients with 64-digit π. Liquid-mass rules and all captured units are retained. The US fluid ounce uses one 128th of the exact US liquid gallon, replacing the rounded captured reciprocal factor. Bookify replaces the captured rounded US gallon with the exact 3.785411784-liter definition. Bookify uses exact customary mass and volume definitions for density units, replacing rounded factors in the reference.

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