Fold & Find
Geometry & space/Cuboid nets & surface area
Upper primary · Middle school

Cuboid nets & surface area3D

Cut a box along its edges. How do its six rectangles lie flat? Change the dimensions, fold the net, and account for every pair of faces.

Set the box dimensions

Drag to rotate · Arrow keys also work

Preparing the 3D cuboid…

Six faces form three pairs

The front and back are both length×height. The top and bottom are both length×width. The left and right are both width×height. Each area appears twice, so add the three areas and multiply by 2.

Surface area2 × (L×W + L×H + W×H)

Example: length 4, width 3, height 2

The three areas are 4×3=12, 4×2=8 and 3×2=6. Surface area = 2×(12+8+6)=52 square units.

Calculate with the current dimensions

The answers change with the length, width and height above.

1

What is the combined area of the top and bottom?

2

What is the total surface area?

Print a practice sheet

The student page uses a 4×3×2 cuboid. Answers print on a separate page.

Geometry & space

Cuboid nets & surface area

Name: ____________
Date: ____________

4×24×34×33×23×24×2

L = 4 · W = 3 · H = 2

  1. Find the combined area of the front and back.
  2. Find the combined area of the top and bottom.
  3. Find the combined area of the left and right.
  4. Find the cuboid’s total surface area.
  5. If only the height changes from 2 to 3, which face areas change?
Geometry & space

Cuboid surface area: answers

  1. 4×2×2=16.
  2. 4×3×2=24.
  3. 3×2×2=12.
  4. 16+24+12=52 square units.
  5. The front/back and left/right change. The top/bottom stay the same.