Circle area & perimeter
Measure circular coverage for garden, flooring and site planning.
Quantity / scenario planning · Reviewed 7 October 2026Your inputs
Check all starting values against your project and product. Enter your own prices; keep costs on the same GST basis.
How to prepare your inputs
Use approved dimensioned plans or verified site measurements. Check units, scale and perpendicular distances.
How this calculation works
Area = π × diameter² ÷ 4. Perimeter = π × diameter.
A 4 m diameter circle has area 12.5664 m² and perimeter 12.5664 m.
Assumptions & exclusions
A full flat circle only. Annular borders, sectors, curved surfaces and installation waste need separate calculations.
Your next step
Confirm quantities against a detailed take-off, project drawings and trade-specific requirements.
Further reading
- Blocklayer geometric tool directory
These resources provide background information. Confirm current product specifications and project requirements with your supplier or trade professional.
What if my shape or product is different?
Use dimensions and product data that match the stated method. For complex work, calculate separate sections or obtain a project-specific take-off. Do not apply simple geometry to structural or compliance decisions.
Why are quantities rounded up?
Whole bags, packs, sheets or cartridges round up to purchasable units. Decimal area or volume results are planning figures; confirm order increments with the supplier.
Are my entries saved?
No. Entries remain in the current browser page and clear on reload. Printing can save your results and inputs as a PDF on your device.
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