Annulus (Ring) Calculator
Result
Annulus (Ring) Calculator The Annulus (Ring) Calculator finds the area, circumferences, and width of a ring — the region between two concentric circles. Enter the outer and inner radii and it returns all the key measurements of the ring. The formulas used — free online calculator.
Formula
- Annulus (Ring) Calculator calculates its result from Outer Radius R (cm), Inner Radius r (cm). It uses the formula Area = π(R²−r²); Outer circumference = 2πR; Inner circumference = 2πr; Width = R−r. Change any input to recalculate the result instantly.
- The main inputs are Outer Radius R, Inner Radius r. Enter them in the units and format shown in the calculator.
- Keep comparable quantities in compatible units whenever the formula combines or compares them.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Annulus (Ring)
- Outer Radius R: 10 cm
- Inner Radius r: 6 cm
For R = 10 cm and r = 6 cm, ring area = 64π ≈ 201.06 cm², outer circumference ≈ 62.83 cm, inner circumference ≈ 37.70 cm and width = 4 cm.
Sample result: Calculating…
Frequently asked questions
What does the Annulus (Ring) calculate?
Annulus (Ring) Calculator The Annulus (Ring) Calculator finds the area, circumferences, and width of a ring — the region between two concentric circles. Enter the outer and inner radii and it returns all the key measurements of the ring. The formulas used — free online calculator.
Which values should I enter?
Enter Outer Radius R, Inner Radius r using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Area = π(R²−r²); Outer circumference = 2πR; Inner circumference = 2πr; Width = R−r.
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.