Calculators
Stadium Calculator
Calculate stadium area, perimeter, overall length, and width from straight section length and semicircle radius.
Measure a rectangle with semicircular ends.
A stadium (also called a discorectangle) consists of a rectangle of length L and width 2r with two semicircles of radius r. L measures only the straight section, not the overall length. Area A = 2rL + πr²; perimeter P = 2L + 2πr; overall length = L + 2r; overall width = 2r. For L = 10 and r = 3, area is approximately 88.2743338823 square units and perimeter is 38.8495559215 units. Set L = 0 for a circle. If you know overall length T and width W, use r = W/2 and L = T − W, with T ≥ W. This is a flat shape, not a three-dimensional capsule. Use consistent length units; areas use squared units. Results use browser floating-point arithmetic rounded to 12 significant digits. All inputs stay in your browser.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What does straight length mean?
It is the length of the rectangular section between the semicircle centers. It excludes the curved ends. Overall length is L + 2r.
Can I enter zero straight length?
Yes. With L = 0 the two semicircles form a circle, with area πr² and perimeter 2πr. Radius must be positive.
How do I use overall dimensions?
Divide overall width by two for radius r. Subtract overall width from overall length for straight section length L. Overall length must be at least the width.
Is this a volume calculator?
No. A stadium is a flat shape. Use the capsule calculator for the volume and surface area of a cylinder with hemispherical ends.