Cone and Cylinder Net Calculator
Find the flat net dimensions for a right circular cone or cylinder. Calculate sector angle or rectangle width, base circles and net surface area.
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Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
A cone unfolds to a sector whose radius is the slant height and whose arc equals the base circumference. A cylinder unfolds to a rectangle of width2πr and height h, plus two base circles.
Cone: l=√(r²+h²), sector angle=360r/l; cylinder rectangle=2πr byh
Worked example
For a cone of radius3cm and height4cm, slant height is5cm. Its net sector angle is216°, sector area15πcm² and base area9πcm².
Assumptions and input details
Radius and perpendicular height must be positive and at most1e12m after conversion. Nets exclude glue tabs, seams, kerf, material thickness and layout nesting. The cone graphic represents the sector, while the separate base circle is listed in the table. The cylinder net diagram is schematic. Surface-area output uses the square of the output length unit.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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