The right shipping box is crucial; it can help you save money and protect your products. Courier companies charge not only based on weight but also on the volumetric weight (DIM weight). If you make a mistake, you could end up paying 15–30% more for shipping. We’ve been designing and producing shipping boxes for over 10 years, helping many clients customize their outer boxes. This article will teach you how to correctly measure boxes and understand the standard shipping box dimensions for different products, helping you avoid pitfalls.
Last updated: September 2025 | Estimated reading time: 6 minutes
This article will answer your questions
- Why shipping box measurements are important?
- How to correctly measure the length, width and height of a box?
- Should you measure the inside or outside diameter of the box?
- Common shipping box sizes for different products
- How box size affects shipping costs and dimensional weight
Why are shipping box measurements important?
Correct shipping box size can reduce costs and damage rates. For lightweight shipments, courier companies like FedEx, UPS, and DHL charge based on volume and weight. A box that’s just 2–3 inches larger than the product can increase shipping costs by 20–30%.
In addition, boxes that are too small may squeeze the products, while boxes that are too large may cause the products to shake or even be damaged, which will also increase additional shipping costs.
The hidden costs of the wrong-sized shipping boxes
| Box Type | DIM Weight Impact | Extra Cost | What It Means for You |
|---|---|---|---|
| Oversized Box | DIM weight increases | +15–30% cost | Unnecessary spending |
| Undersized Box | Higher damage rate | More returns | Profit loss |
| Right-Sized Box | Balanced cost and safety | Minimal extra fees | Efficient and secure |
Our tips for you:
- Always measure the inside diameter → the outside diameter includes the cardboard thickness, which can lead to errors
- Reserve buffer space → for filling bubble bags, corner protectors, and foam
- Consider pallet optimization → Export cartons must fit European standard pallets (1200 × 1000mm)
A typical success story: A US brand reduced its air freight costs by 22% after reducing the carton size from 18 × 14 × 8 inches to 16 × 12 × 6 inches. The product still fits into the foam tray, but the volume weight is reduced from 8kg to 6kg.
See our corrugated packaging boxes page.
How to measure the length, width and height of a box?
Industry rule: Always measure the inside diameter.
- Length: Measure the longest side of the opening from one end to the other with a tape measure, and then round off to get the length.
- Width: Measure the shorter side of the opening, also the vertical length, from one end to the other with a tape measure, and then round off to get the width.
- Height/Depth: Measure from the bottom to the top of the box and round up to get the exact height.
Common measuring tools
Steel ruler or tape measure → Measure the length, width, and height of the shipping box, the most common three-dimensional dimensions.
Vernier caliper → High precision, suitable for measuring the size of inner boxes or trays.
Carton measuring machine → Generally used in carton factories, fast speed.
Should you measure the inside or outside diameter?
Always measure the inside diameter because:
- The actual space for placing the product depends on the internal dimensions of the shipping box.
- The thickness of corrugated cardboard is generally 5-10mm, and we will also confirm it based on your actual product weight.
- Our factory designs and opens molds based on the inner diameter.
Common shipping box sizes for different products
Below is a table showing typical sizes for some products.
| Product Type | Common Box Size | Protection Notes |
|---|---|---|
| Clothing | 12 × 9 × 4 in | T-shirts, small apparel |
| Electronics | 18 × 14 × 6 in | Laptops, electronic devices |
| Jewelry | 6 × 6 × 4 in | Rigid insert or small gift box required |
| Perfume | 8 × 6 × 4 in | Foam or blister tray |
| Cookies | 10 × 10 × 4 in | Food-grade liner |
| CBD Products | 6 × 4 × 2 in | Oils, vapes, small jars |
| Pizza | 10, 12, 14, 16 in | With vent holes |
How does box size affect shipping costs?
For heavy goods, express companies charge according to the actual weight; for light goods, they charge according to the volume weight. The formula for calculating volume weight is:
Volume weight (kg) = length (cm) × width (cm) × height (cm) / 6000
For example, a 2kg product placed in a box that is too large may be charged as 6kg. Choose the right box to balance protection and shipping costs.
FAQs
A steel ruler or tape measure will suffice. For highly accurate measurements, a vernier caliper can be used. Larger factories use carton measuring machines.
It is recommended to leave 1-2 inches around the product for bubble wrap, foam, or corner protectors.
Don't measure the outside diameter, don't confuse width with height, and don't ignore the thickness of the cardboard. Confirm with the carton factory which three dimensions the length, width, and height refer to.
Conclusion
Properly measuring shipping boxes can reduce shipping costs and damage rates. Always measure by the inside diameter, follow the length, width, and height guidelines, and allow for cushioning. Common shipping box sizes will accommodate most products, but custom-sized boxes offer maximum protection and cost savings.
About XiangGe Package
XiangGe specializes in providing customized shipping boxes and packaging solutions for global brands. Our factory manufactures corrugated boxes, gift boxes, and trays, serving a wide range of industries, including electronics, apparel, and food. With over 10 years of export experience, we help our customers optimize their packaging, achieving a balance between safety and cost.
Contact us to customize shipping boxes for your products or request a custom die-line.
Last updated: September 2025
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