Surface Area of a Rectangular Prism Calculator

Calculate the total surface area of a rectangular prism (box) with a breakdown of each pair of faces.

Enter Dimensions

Result

Total Surface Area
--
square units
Top & Bottom (l x w) x 2--
Front & Back (l x h) x 2--
Left & Right (w x h) x 2--
Volume--
Space Diagonal--

Step-by-Step Solution

SA = 2(lw + lh + wh)

Understanding Rectangular Prism Surface Area

A rectangular prism (also called a cuboid or box) is a three-dimensional shape with six rectangular faces. Each pair of opposite faces is congruent, so the surface area is computed by summing the areas of three distinct face pairs and doubling.

Face Pairs

Top & Bottom

Two faces with dimensions length by width.

2 x l x w

Front & Back

Two faces with dimensions length by height.

2 x l x h

Left & Right

Two faces with dimensions width by height.

2 x w x h

Applications

Rectangular prisms are the most common 3D shape in daily life: boxes, rooms, buildings, shipping containers, books, and electronics. Calculating their surface area is essential for packaging design, painting walls, wrapping gifts, and material estimation in construction.

Special Cases

  • When all three dimensions are equal, the shape is a cube with SA = 6s^2.
  • When one dimension is zero, the shape degenerates to a flat rectangle.
  • The space diagonal of a rectangular prism is sqrt(l^2 + w^2 + h^2).
  • For a given volume, a cube has the minimum surface area among all rectangular prisms.