How to Measure Irregular Shaped Items (Cylinders & L-Shapes)

Our CBM Calculator works perfectly for square boxes. But what if you are shipping Rug Tubes, Industrial Pipes, or L-shaped Sofas?

Shipping carriers do not calculate volume based on the exact shape of the object. They use a method called the Minimum Bounding Box.

The Golden Rule: “Square the Circle”

Logistics companies treat every object as if it were inside a rectangular box. They measure the extreme points of the length, width, and height.

1. Cylinders (Tubes, Rolls, Pipes)

If you are shipping a poster tube or a roll of fabric:

• The Mistake: Using the formula pi * r^2 * h (Volume of a cylinder).
• The Reality: The carrier stacks them as if they are square.

How to Measure:

1. Diameter: Measure the widest part of the circle. This becomes BOTH the Width and the Height.
2. Length: Measure the tube from end to end.

Formula: Diameter × Diameter × Length = CBM Volume

Example: A tube is 1 meter long and 0.2m in diameter.

• Wrong (Math Volume): 0.031 CBM
• Correct (Shipping Volume): 0.2 * 0.2 * 1 = 0.04 CBM

2. Pyramids or Cones

If you ship a stack of traffic cones:

1. Measure the widest point of the base (Width/Length).
2. Measure the highest point (Height).
3. Multiply L * W * H. You pay for the empty air around the pointy top.

3. L-Shaped Furniture (e.g., Sectional Sofas)

If you ship an L-shaped desk that isn’t disassembled:

1. The carrier draws an imaginary rectangle around the entire “L”.
2. You pay for the massive empty space in the crook of the “L”.

The Fix: Always disassemble irregular furniture into flat rectangular boxes (“Flat Pack”). This can reduce your freight costs by 50% or more.

Why Do Carriers Do This?

It isn’t just to charge you more. It is about stackability. If you have a cylinder, you cannot easily stack other boxes on top of it without them falling off. The “lost space” around the cylinder is unusable for other cargo, so you are charged for it.

Conclusion

When entering dimensions into our CBM Calculator, always imagine your object is inside a tight rectangular box. Enter the dimensions of that box to get the accurate shipping cost.