Surface Area of a Cuboid Calculator

Published on: July 21, 2024

This Surface Area of a Cuboid Calculator helps you find the total area of all faces of a cuboid when the length, width, and height are known. It uses the formula SA = 2(lw + lh + wh), where l is the length, w is the width, h is the height, and the answer is written in square units. Find the areas of the three different face pairs, add them together, then multiply by 2 to get the surface area. It is a simple way to check answers, understand the cuboid surface area formula, and practise basic geometry step by step.
Cuboid labeled l, w, h
In the diagram, the dimensions are labeled l, w, and h.

Step-by-step method

  1. Identify what is given.
  2. Write the formula.
  3. Substitute the values and calculate the surface area.

Formula:

A = 2(lw + lh + wh)

Example 1: l = 4, w = 3, h = 2

Step 1 - Identify what is given.

In this problem: The given dimensions are l = 4, w = 3, h = 2.

l=4,w=3,h=2

Step 2 - Write the formula.

In this problem: Use the surface area formula: A = 2(lw + lh + wh).

A=2(lw + lh + wh)

Step 3 - Substitute the values and calculate the surface area.

In this problem: Substitute l = 4, w = 3, h = 2: A = 2((4×3) + (4×2) + (3×2)). Then A = 2(12 + 8 + 6) = 52.

A=2((4×3) + (4×2) + (3×2))=52

Final answer: A = 52

Example 2: l = 6.5, w = 2, h = 1.5

Step 1 - Identify what is given.

In this problem: The given dimensions are l = 6.5, w = 2, h = 1.5.

l=6.5,w=2,h=1.5

Step 2 - Write the formula.

In this problem: Use the surface area formula: A = 2(lw + lh + wh).

A=2(lw + lh + wh)

Step 3 - Substitute the values and calculate the surface area.

In this problem: Substitute l = 6.5, w = 2, h = 1.5: A = 2((6.5×2) + (6.5×1.5) + (2×1.5)). Then A = 2(13 + 9.75 + 3) = 51.5.

A=2((6.5×2) + (6.5×1.5) + (2×1.5))=51.5

Final answer: A = 51.5