Enter radius values and click Calculate to see results.
Enter radius values and click Calculate to see step-by-step solution.
Area of Annulus: A = π(r₂² - r₁²)
Outer Circumference: C₂ = 2πr₂
Inner Circumference: C₁ = 2πr₁
Total Circumference: C = C₁ + C₂ = 2π(r₁ + r₂)
Thickness: t = r₂ - r₁
Outer Diameter: D₂ = 2r₂
Inner Diameter: D₁ = 2r₁
An annulus (or ring) is a flat, circular region bounded by two concentric circles. It's the shape that results when you take a circle and remove a smaller circle from its center.
The key parameters of an annulus are its inner radius (r₁) and outer radius (r₂). These determine all other properties like area, circumference, and thickness.