Surface Area Calculator
Calculate the surface area of cubes, spheres, cylinders, cones, and other 3D shapes instantly
Enter the triangle base dimensions and the three side lengths.
Total Surface Area of
square units
Lateral Surface Area
Curved/Side surfaces
Base Area
Top & bottom surfaces
Slant Height
Calculated: l = √(r² + h²)
Formula Used
SA = square units
Surface Area Formula Reference
SA = 6a²
SA = 2(lw+lh+wh)
SA = 4πr²
SA = 2πr(r+h)
SA = πr(r+l)
SA = a²+2al
SA = bh+(a+b+c)L
SA = 3πr²
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About Surface Area Calculator
What is a Surface Area Calculator?
A surface area calculator is a mathematical tool that helps you determine the total area of all surfaces on three-dimensional (3D) shapes. Unlike area calculators for 2D shapes, surface area measures the entire outer covering of a solid object—essential for construction, manufacturing, packaging, and scientific applications.
How to Use This Calculator
- Select a 3D shape: Choose from 8 common solid shapes (cube, sphere, cylinder, etc.)
- Enter measurements: Input the required dimensions for your chosen shape
- View results: Instantly see the calculated surface area with the formula used
- Compare shapes: Switch between shapes to analyze surface areas for different solids
Supported Shapes and Formulas
Cube
Formula: SA = 6a²
A cube has 6 identical square faces. Multiply the area of one face by 6.
Rectangular Prism (Box)
Formula: SA = 2(lw + lh + wh)
Add the areas of all 6 rectangular faces (3 pairs of identical faces).
Sphere
Formula: SA = 4πr²
Multiply 4 times pi times the square of the radius.
Cylinder
Formula: SA = 2πr(r + h)
The surface includes 2 circular bases plus the curved lateral surface (2πrh).
Cone
Formula: SA = πr(r + l) where l = √(r² + h²)
The surface includes the circular base (πr²) plus the lateral surface (πrl). The slant height (l) is calculated from the radius and height.
Square Pyramid
Formula: SA = a² + 2a√(a²/4 + h²)
The surface includes the square base plus 4 triangular faces. The slant height is calculated from the base half-width and height.
Triangular Prism
Formula: SA = bh + (a + b + c)L
The surface includes 2 triangular bases plus 3 rectangular lateral faces.
Hemisphere
Formula: SA = 3πr²
The surface includes the curved dome (2πr²) plus the flat circular base (πr²).
Real-World Applications
Construction & Architecture
- Calculating paint or coating needed for walls, domes, and tanks
- Estimating insulation material for cylindrical pipes or spherical tanks
Manufacturing & Packaging
- Determining material needed for boxes, cans, and containers
- Optimizing packaging to minimize material costs
Science & Engineering
- Calculating heat transfer rates (proportional to surface area)
- Designing pressure vessels and storage tanks
Frequently Asked Questions
What's the difference between surface area and volume?
Surface area measures the total outer covering of a 3D shape (in square units), while volume measures the space inside the shape (in cubic units).
What units should I use?
You can use any unit (inches, feet, meters, etc.), but be consistent. The resulting surface area will be in square units.
How do I find the slant height?
For cones and pyramids, the slant height (l) is calculated using the Pythagorean theorem: l = √(r² + h²) for cones or l = √((a/2)² + h²) for square pyramids.
Why is surface area important?
Surface area determines how much material is needed to cover or coat an object, affects heat exchange rates, and influences chemical reaction speeds.
Tip: Always measure to the outer edge of objects. For hollow objects, you may need to calculate inner and outer surface areas separately.