What is a rectangular prism?

A rectangular prism (also called a cuboid) is a 3D solid with six rectangular faces, where every pair of opposite faces is identical. A standard cardboard box is a common example.

What is the formula for surface area of a rectangular prism?

SA = 2(lw + lh + wh), where l is length, w is width, and h is height. This sums the area of all six faces.

How is lateral surface area different from total surface area?

Lateral surface area counts only the four side faces: LSA = 2(l + w) x h. Total surface area adds the top and bottom: TSA = 2(lw + lh + wh).

What units does this calculator use?

Enter dimensions in any unit (cm, m, inches, feet). The result is in the square of that unit. Use the same unit for all three dimensions.

What is the difference between surface area and volume?

Surface area measures the total area of the outer faces (square units). Volume measures the space inside the prism (cubic units, V = l x w x h).

Can I see the area of one face?

Yes. The breakdown shows the three unique face-pair areas: 2lw (top and bottom), 2lh (front and back), and 2wh (left and right). Halve any pair for a single face.

Surface Area of a Rectangular Prism Calculator

Name: Surface Area of a Rectangular Prism Calculator
Availability: InStock
Author: Nham Vu

Enter the length, width, and height of a rectangular prism to instantly calculate its total surface area.

Rectangular Prism Dimensions

Length (l)

Width (w)

Height (h)

Unit (optional label)

Formula

SA = 2(lw + lh + wh)

Enter length, width, and height to see the result

Copied!

Summary

Enter the length, width, and height of a rectangular prism to instantly calculate its total surface area.

How it works

Enter the length (l), width (w), and height (h) of the rectangular prism.
Pick an optional unit label (mm, cm, m, in, ft) so the result is shown in the correct squared unit.
The calculator applies SA = 2(lw + lh + wh) — the sum of the three opposite face pairs.
View the total surface area, the worked calculation, and the per-face-pair breakdown.

Use cases

Estimate how much wrapping material is needed to cover a box.
Calculate the paint required to coat a rectangular container.
Price the cardboard sheet needed to manufacture a packaging run.
Verify surface area homework answers for grade-6 to grade-8 geometry.
Compute heat dissipation area for a rectangular electronic enclosure.

Frequently Asked Questions

Last updated: 2026-06-13 · Reviewed by Nham Vu