Box Net Area Calculator
Work out the surface area of a rectangular box (cuboid) and how much wrapping paper and ribbon you need to gift-wrap it. Enter the length, width, and height to see the total surface area, paper with overlap, and ribbon length.
Formula
SA = 2lw+2lh+2wh; Wrapping = SA×1.2; Ribbon = 2(l+w)+2(l+h)+30cm
8 × 5 × 3 cm box
Inputs
- Length: 8 cm
- Width: 5 cm
- Height: 3 cm
Surface area = 2(8×5) + 2(8×3) + 2(5×3) = 80 + 48 + 30 = 158 cm². With 20% overlap you need about 190 cm² of paper, plus roughly 62 cm of ribbon including a 30 cm bow allowance.
Frequently asked questions
How is a box's surface area calculated?
Add up the areas of all six faces: 2(length×width) + 2(length×height) + 2(width×height).
Why add 20% for wrapping paper?
Wrapping needs overlap at the seams and ends to fold neatly, so a 20% allowance gives enough paper to cover the box without gaps.
How is the ribbon length worked out?
It wraps around the box in both directions — 2(length+width) + 2(length+height) — plus an extra 30 cm for tying a bow.
What units should I use?
Enter all three dimensions in the same unit (the defaults use centimetres). Areas come out in square units and ribbon in linear units.
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