Pipe Formulas

Pipe and Tube Equations - moment of inertia, section modulus, traverse metal area, external pipe surface and traverse internal area - imperial units

The calculator is based on the piping formulas and equations below:

Moment of inertia can be expressed as

I = 0.0491 (d_o⁴ - d_i⁴) (1)

where

I = moment of inertia (in⁴)

d_o = outside diameter (in)

d_i = inside diameter (in)

Section modulus can be expressed as

Z = 0.0982 (d_o⁴ - d_i⁴) / d_o (2)

where

Z = section modulus (in³)

Transverse metal area can be expressed as

A_m = π (d_o² - d_i²) / 4 (3)

where

A_m = transverse metal area (in²)

External pipe or tube surface per ft of length can be expressed as

A_o = π d_o / 12 (4)

where

A_o = external pipe surface area (ft² per ft pipe)

Internal pipe or tube surface per ft of length can be expressed as

A_i = π d_i / 12 (5)

where

A_i = internal pipe surface area (ft² per ft pipe)

Transverse internal area can be expressed as

A_a = 0.7854 d_i² (6)

where

A_a = transverse internal area (in²)

External circumference can be expressed as

C_e = π d_o (7)

where

C_e = external circumference (in)

Internal circumference can be expressed as

C_i = π d_i (8)

where

C_i = internal circumference (in)

9 12 8