Cone Surface Area Calculator

Calculate the surface area of a cone by entering the base radius and height. A cone has a circular base and curved surface meeting at a point.

🔺 Cone Surface Area

Formula

Total Surface Area: SA = πr(r + l)
Slant Height: l = √(r² + h²)
Where r is the base radius, h is the height, and l is the slant height

Cone Surface Area Formulas

Total Surface Area

SA = πr(r + l)

Includes the circular base and the curved surface

Lateral Surface Area

LSA = πrl

Only the curved surface, excluding the base

Slant Height

l = √(r² + h²)

Distance from apex to base edge along the surface

Volume

V = (1/3)πr²h

Volume of the cone

Cone Surface Area Examples

Example 1: Small Cone

Given: Radius = 3 cm, Height = 4 cm

Slant Height: l = √(3² + 4²) = √25 = 5 cm

Formula: SA = πr(r + l)

Solution: SA = π × 3 × (3 + 5) = 3π × 8 = 24π ≈ 75.40 cm²

Example 2: Medium Cone

Given: Radius = 5 cm, Height = 12 cm

Slant Height: l = √(5² + 12²) = √169 = 13 cm

Formula: SA = πr(r + l)

Solution: SA = π × 5 × (5 + 13) = 5π × 18 = 90π ≈ 282.74 cm²

Example 3: Large Cone

Given: Radius = 8 cm, Height = 15 cm

Slant Height: l = √(8² + 15²) = √289 = 17 cm

Formula: SA = πr(r + l)

Solution: SA = π × 8 × (8 + 17) = 8π × 25 = 200π ≈ 628.32 cm²

Cone Surface Area FAQ

What is a cone?

A cone is a 3D shape with a circular base and a curved surface that tapers to a single point (apex). Common examples include ice cream cones and traffic cones.

What is slant height?

Slant height is the distance from the apex to any point on the base circumference, measured along the cone's surface. It's calculated as l = √(r² + h²).

What's the difference between height and slant height?

Height (h) is the vertical distance from base to apex. Slant height (l) is the distance along the cone's surface from apex to base edge.

How do you calculate cone surface area?

Total surface area uses SA = πr(r + l), which includes the base and curved surface. Lateral surface area uses LSA = πrl for just the curved part.