What is the formula for the surface area of a cuboid?

SA = 2(lw + lh + wh), where l is length, w is width, and h is height. The formula sums the area of all six rectangular faces in three pairs.

What units does this calculator use?

The calculator is unit-agnostic. Enter values in any consistent unit (centimeters, meters, inches, feet) and the result is expressed in the square of that unit (e.g., cm²).

What is the difference between total and lateral surface area?

Total surface area includes all six faces. Lateral surface area includes only the four side faces and excludes the top and bottom (SA_lateral = 2h(l + w)).

Can I use decimal or fractional values?

Yes. The calculator accepts any positive decimal number, such as 3.5 or 0.25.

Is a cube a special case of a cuboid?

Yes. A cube is a cuboid where all three dimensions are equal (l = w = h), giving SA = 6l².

Surface Area of a Cuboid Calculator

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

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

Cuboid Dimensions

Length (l)

Width (w)

Height (h)

Unit

Results

Enter dimensions and click Calculate

Summary

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

How it works

Enter the length, width, and height of your cuboid in any unit.
The calculator applies the formula SA = 2(lw + lh + wh) in real time.
Results show the total surface area plus a per-face-pair breakdown.
Change the unit label (cm, m, in, ft) to keep your results clearly annotated.
Copy the result to your clipboard with one click.

Use cases

Calculating how much material is needed to wrap or paint a box.
Homework and exam prep for geometry and mensuration topics.
Estimating the surface area of rooms, tanks, or packaging.
Verifying manual calculations quickly during engineering projects.
Teaching the cuboid surface area formula interactively.
Finding the exposed area of a rectangular solid in physics problems.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu