Cross Sectional Area Calculator - Amesweb

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Cross Sectional Area Calculator

Calculate cross sectional area of circle, pipe/tube, cylinder, rectangle and beam sections

Cross sectional area Section properties calculator Beam & channel sizes W beam sizes

Use this cross sectional area calculator to calculate cross sectional area for common shapes: circle, pipe/tube (hollow circle), cylinder, hollow cylinder, rectangle, hollow rectangle, and structural sections like I‑beam, C channel, T section, and angle.

Popular searches: cross sectional area formula · cross sectional area of a cylinder · pipe cross sectional area calculator · i beam area calculator.

Circle (round bar / shaft)

A = π d² / 4 d = diameter

Pipe / Tube (hollow cylinder)

A = π (D² − d²) / 4 D = outer diameter, d = inner diameter

Rectangle

A = B H B = width, H = height

Hollow rectangle

A = B H − b h Outer B×H minus inner b×h

Triangle

A = B H / 2 Base B, height H

Equilateral triangle

A = √3 a² / 4 a = side length

Cross sectional area formulas (quick reference)

Shape	Cross section area formula
Circle (diameter d)	A = π d² / 4
Pipe / tube (outer D, inner d)	A = π (D² − d²) / 4
Rectangle (B × H)	A = B H
Hollow rectangle (outer B×H, inner b×h)	A = B H − b h
Isosceles / general triangle (base B, height H)	A = B H / 2
Equilateral triangle (side a)	A = √3 a² / 4

Inputs

Cross section shape I Beam Hollow Rectangle Rectangle C Channel T Section Circular Hollow Section (pipe/tube) Round Bar (circle) Angle (unequal legs) Isosceles triangle Equilateral triangle Input length unit mm cm m inch ft Output area unit mm^2 cm^2 inch^2 ft^2 H (inner height) B (width) h (thickness) b (thickness)

Note: Use dot "." as decimal separator.

Results

Parameter	Value
Cross section area (A)	---

Copy result Copied

How to use this calculator

1. Select a cross section shape (for example, circle/shaft, pipe/tube, rectangle, or I‑beam).
2. Enter the required dimensions (only the inputs needed for the selected shape are shown).
3. Choose your input length unit (mm, cm, m, inch, ft) and output area unit (mm², cm², in², ft²).
4. The cross sectional area A updates automatically. Use Copy result for quick reporting.

Engineers use cross section area in calculations for stress (σ = F/A), mass/weight estimates, and sizing of shafts, pipes, and structural members.

Related engineering tools

• Section properties calculator (I, S, r, centroid)
• Wide flange (W) beam sizes chart
• Standard beam & channel sizes
• Metric hex nut sizes

FAQ

How do I calculate cross sectional area?

Choose the shape, enter dimensions, and the tool outputs area A in your selected units. For example, a circle uses A = π d² / 4 and a pipe/tube uses A = π (D² − d²) / 4.

What is the cross sectional area of a cylinder?

For a solid cylinder, the cross section perpendicular to the axis is a circle, so A = π d² / 4. For a hollow cylinder (pipe/tube), A = π (D² − d²) / 4.

What units does this calculator support?

You can work in metric or inch systems. Select the input length unit and output area unit from the dropdowns.