Radius + height to exact sector
Custom Cone Net Generator
Enter the base radius and vertical height. The tool calculates the slant height and sector angle, then builds a printable side sector and circular base.
Advanced settings · layouts, labels & printing
Worked example
Cone example: radius 2 cm, height 4 cm
With radius 2 cm and vertical height 4 cm, the slant height is √20 ≈ 4.47 cm. The side sector has radius 4.47 cm and angle about 161°. Its curved edge is 4π ≈ 12.57 cm long, matching the circular base.
Vertical height goes from the base center to the tip. Slant height runs along the cone surface.
The flat pattern contains a sector and a separate circular base. The 3D preview shows the finished cone; it does not animate the curved paper wrapping.
How to print and assemble
- Enter radius and vertical height, download the PDF and check the printed calibration line.
- Cut out the sector and base with their tabs. Gently curl the sector around a marker.
- Bring the straight sector edges together with the seam tab underneath, then glue the base tabs inside the cone.
The geometry
Cone net formula
Slant height L = √(r² + h²). The sector radius is L and its angle is 360° × r ÷ L, so its curved edge matches the base circumference.
Quick answers
Frequently asked questions
Why is a cone net a sector?+
The curved surface opens into part of a circle. Its outer arc must equal the circumference of the cone base.
Does the template include a base?+
Yes. The generated net contains the side sector, a separate circular base and segmented glue tabs.
Can I animate the cone folding?+
The tool shows the exact flat net and a rotatable finished cone. Continuous curved-surface folding is not simulated.