Surface Area of a Frustum Calculator
Enter the top radius, bottom radius, and slant height of a frustum to instantly get the lateral and total surface area.
Frustum Dimensions
cm
cm
cm
Formula Reference
Lateral Surface Area
LSA = π(R+r)l
Top Circle Area
A₁ = π · r²
Bottom Circle Area
A₂ = π · R²
Total Surface Area
TSA = LSA + A₁ + A₂
Enter the dimensions, then click Calculate Surface Area.
Total Surface Area
—
cm²
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Lateral Surface Area
—
cm²
Top Circle Area
—
cm²
Bottom Circle Area
—
cm²
Frustum Diagram
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Summary
Enter the top radius, bottom radius, and slant height of a frustum to instantly get the lateral and total surface area.
How it works
- Enter the bottom (larger) radius of the frustum.
- Enter the top (smaller) radius of the frustum.
- Enter the slant height — the distance along the slanted side from edge to edge.
- Select your preferred unit (cm, m, in, or ft).
- The lateral surface area, both base areas, and total surface area are computed instantly.
- Use the Copy button to copy the total surface area to your clipboard.
Use cases
- Calculate material needed to cover a conical lampshade or bucket.
- Estimate sheet metal required for a tapered pipe or duct section.
- Solve geometry homework on frustum surface areas.
- Determine fabric or wrapping for cone-frustum packaging.
- Compute heat-transfer surface for tapered industrial vessels.
- Verify 3D model surface area during product design.
- Calculate paint coverage for conical storage tanks.
- Find the net area of a truncated cone for pattern-making.
Frequently Asked Questions
Last updated: 2026-06-13 ·
Reviewed by Nham Vu