Annulus Calculator
A = π(R² − r²) — ring between two concentric circles
An annulus (ring) is the region between two concentric circles — an outer circle of radius R and an inner circle of radius r. It appears in engineering (pipe cross-sections), design, and optics.
References
🔒
100% Free
No sign-up ever
✓
Accurate
Verified formulas
⚡
Instant
Results as you type
📱
Mobile Ready
All devices