Stadium Calculator
Calculate the area and perimeter of a stadium shape (discorectangle) — a rectangle capped by two semicircles — from the straight side length and radius.
Everyday Uses
Running tracks
Tracks are stadium-shaped — compute the enclosed area and perimeter for events or turf.
Pools and ponds
Many pools have rounded ends — get true area for covers, liners, and chemicals.
Table and rug sizing
Racetrack tables and rugs need stadium math for glass tops or floor space.
Design layouts
Buttons, badges, and pill shapes in design are stadiums — size them precisely.
Frequently Asked Questions
What is a stadium shape?
A stadium (also called a discorectangle or obround) is a rectangle with a semicircle attached to each of two opposite sides. It is the shape of an athletics running track, a pill capsule, or many ice rinks. It is defined by two values: the straight side length (a) and the radius (r) of the semicircular ends.
How do you calculate the area of a stadium?
Area = πr² + 2ra. The two semicircles together form one full circle (πr²), and the central rectangle measures a × 2r. Example: a = 10, r = 3 gives Area = π×9 + 2×3×10 = 28.27 + 60 = 88.27.
How do you calculate the perimeter of a stadium?
Perimeter = 2πr + 2a — the two semicircular ends form a full circle circumference (2πr), plus the two straight sides (2a). A standard 400 m running track is a stadium shape: two 84.39 m straights and two semicircular bends of radius ≈ 36.5 m measured on the inside lane.
Where is the stadium shape used in real life?
Running tracks, ice hockey rinks, pill and capsule design, stadium seating outlines, slot-shaped holes in engineering (drilled slots), UI design (pill-shaped buttons), and architecture. In engineering drawings the shape is usually called an obround or slot.