Annulus Area Calculator: 4 units Outer Radius (R); 2 units Inner Radius (r)

Specific conversion page with reference context, calculator, and nearby values.

Author

Prof. Chen Wei

Math editorial contributor

Chinese AI ethics researcher at Tsinghua University, publishing extensively on algorithmic bias in hiring systems

Reviewed by

Dr. Emeka Nwosu

Math content reviewer

Nigerian legal scholar with an SJD from Yale, focused on international trade law and African continental free trade agreements

Last updatedFebruary 22, 2026

PublishedFebruary 22, 2026

Table of Contents

  1. Value details
  2. Calculator
  3. Nearby reference values
  4. FAQs
  5. Methodology and review
  6. Navigation and related conversions

4 units Outer Radius (R); 2 units Inner Radius (r) converts to

37.6991 sq units

Use this as a quick reference for Annulus Area Calculator.

Value Details

Input: 4 units Outer Radius (R); 2 units Inner Radius (r)

Output: 37.6991 sq units

Browse all reference values for Annulus Area Calculator

Annulus Area Calculator

Calculate annulus area from outer and inner radius using A = π(R² - r²).

Calculated Result

Nearby Reference Values

Annulus Area Calculator values near 4 units Outer Radius (R); 2 units Inner Radius (r)
ScenarioAnnulus Area
2 units Outer Radius (R); 0.5 units Inner Radius (r)11.781 sq units
2 units Outer Radius (R); 1 units Inner Radius (r)9.4248 sq units
2 units Outer Radius (R); 1.5 units Inner Radius (r)5.4978 sq units
3 units Outer Radius (R); 0.5 units Inner Radius (r)27.4889 sq units
3 units Outer Radius (R); 1 units Inner Radius (r)25.1327 sq units
3 units Outer Radius (R); 1.5 units Inner Radius (r)21.2058 sq units
3 units Outer Radius (R); 2 units Inner Radius (r)15.708 sq units
4 units Outer Radius (R); 0.5 units Inner Radius (r)49.4801 sq units
4 units Outer Radius (R); 1 units Inner Radius (r)47.1239 sq units
4 units Outer Radius (R); 1.5 units Inner Radius (r)43.1969 sq units
4 units Outer Radius (R); 2 units Inner Radius (r)37.6991 sq units
4 units Outer Radius (R); 3 units Inner Radius (r)21.9911 sq units
5 units Outer Radius (R); 0.5 units Inner Radius (r)77.7544 sq units
5 units Outer Radius (R); 1 units Inner Radius (r)75.3982 sq units
5 units Outer Radius (R); 1.5 units Inner Radius (r)71.4712 sq units
5 units Outer Radius (R); 2 units Inner Radius (r)65.9734 sq units
5 units Outer Radius (R); 3 units Inner Radius (r)50.2655 sq units
8 units Outer Radius (R); 0.5 units Inner Radius (r)200.2765 sq units
8 units Outer Radius (R); 1 units Inner Radius (r)197.9203 sq units
8 units Outer Radius (R); 1.5 units Inner Radius (r)193.9933 sq units
8 units Outer Radius (R); 2 units Inner Radius (r)188.4956 sq units

Frequently Asked Questions

Common questions about Annulus Area Calculator, formulas, and expected usage.

What does the Annulus Area Calculator calculator do?

It helps with finding ring-shaped area for washers, gaskets, and circular cutouts.

What formula does the Annulus Area Calculator calculator use?

Annulus area = π × (outer radius² - inner radius²).

What inputs are valid?

Outer radius must be greater than inner radius, and inner radius cannot be negative.

When would I use this?

finding ring-shaped area for washers, gaskets, and circular cutouts

Methodology and Review

This page is generated from the same conversion definition used by the main calculator page, which keeps the calculator, reference table rows, and FAQ schema aligned.

Reviewer and update metadata are shown above and included in structured data. See our editorial policy, review process, and corrections policy.

Use this page as a fast lookup reference, then confirm final project values using applicable standards and manufacturer documentation.