Convertools

Annulus Area Calculator

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

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. Reference values
  2. Calculator
  3. Reference table
  4. FAQs
  5. Methodology and review
  6. Related conversions

4 units Outer Radius (R); 3 units Inner Radius (r) =

21.9911 sq units

Representative value from the Annulus Area Calculator reference table.

Reference Values

Browse 22 reference values with individual detail pages for quick lookup.

Browse all reference values

Annulus Area Calculator

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

Calculated Result

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Reference Table

Use this complete table for quick lookup and internal linking to specific value pages.

Annulus Area Calculator Reference
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
8 units Outer Radius (R); 3 units Inner Radius (r)172.7876 sq units

Frequently Asked Questions

Common questions about Annulus Area Calculator, formulas, and typical use cases.

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 combines a live calculator, precomputed reference values, and FAQ content from the same conversion definition to reduce mismatch between calculator output and lookup tables.

Editorial metadata (author, reviewer, and update date) is rendered on the page and in structured data. See our editorial policy, review process, and corrections policy.

For compliance-sensitive work, verify final values against project requirements, governing standards, and manufacturer documentation.