Cross Sectional Area Calculator

Cross-Sectional Area Calculator

Compute the area of common engineering cross-sections from their measured dimensions.

Last updated: June 2026 | By Patchworkr Team

Area
78.53981634
square units
Perimeter: 31.41592654

Formulas

Circle: A = pi r^2
Rectangle: A = w h
Triangle: A = 1/2 b h
Trapezoid: A = 1/2 (b1 + b2) h
I-beam: A = 2(fw ft) + wh wt

Perimeter is exact only for the circle and rectangle with the provided inputs.

How to Use

1. Choose the cross-section shape.

2. Enter the dimensions that define that shape.

3. Read the live area result and the perimeter note.

Worked Example

For a rectangle 10 by 8:

A = 10 * 8 = 80

P = 2(10 + 8) = 36

FAQ

Why is perimeter missing for some shapes?

The provided dimensions do not uniquely determine the boundary length.

Are the area formulas exact?

Yes, for the dimensions the calculator asks for.

Can I use decimals?

Yes, as long as the values are finite real numbers.

Does the I-beam formula include corner radii?

No. It uses a simplified rectangular cross-section model.

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