158 square units
Surface Area Calculator
Use this free surface area calculator to find outside area for rectangular prisms, cubes, cylinders, spheres, and cones with formula steps.
Formula steps Examples included Copy results Private history
SA = 2lw + 2lh + 2wh158 cm^2
- Length
- 8 cm
- Width
- 5 cm
- Height
- 3 cm
Steps
- Choose rectangular prism mode.
- Use SA = 2lw + 2lh + 2wh.
- Substitute the entered measurements.
- The surface area is 158 cm^2.
How to use the surface area calculator
- Choose the solid shape: rectangular prism, cube, cylinder, sphere, or cone.
- Enter the required measurements for that shape.
- Press Calculate surface area to see the square-unit result and formula steps.
- Use examples, recent answers, or copy the result while checking geometry work.
Common uses
Find the outside area of common 3D solids.
Compare surface area for boxes, cylinders, spheres, and cones.
Check square-unit answers for geometry homework.
Copy formulas and results into notes while comparing shapes.
Examples
201.06192983 square units
245.04422698 square units
Frequently asked questions
Quick answers about formulas, units, valid measurements, examples, copying, and private in-browser history.
Which shapes are supported?
The Surface Area Calculator supports rectangular prism, cube, cylinder, sphere, and cone modes.
What units should I use?
Use the same length unit for every measurement. The result is reported in square units, such as cm^2 or ft^2.
How does cone surface area work?
Cone surface area uses pi r(r + l). This calculator finds slant height l from radius and vertical height using the Pythagorean theorem.
What is the difference between surface area and volume?
Surface area measures the outside of a solid in square units. Volume measures the space inside a solid in cubic units.
Can this calculate flat 2D shapes?
Use the Area Calculator for flat shapes such as rectangles, triangles, circles, trapezoids, and parallelograms.
Is my surface area history private?
Yes. Recent surface area answers stay only in the current browser tab while you use the page. They are not sent to a server.