In the packaging industry, dimensions are always stated in internal measurements and written in a standard order:
Length (L) × Width (W) × Depth (D or Height)
### 1. The Standard Packaging Formula:
- Length (L): The longest side of the box opening.
- Width (W): The shorter side of the box opening.
- Depth / Height (D or H): The vertical distance from the top opening down to the base of the box.
- Internal Dimensions (Crucial for Product Fit): Measures the usable space inside the box. Corrugated cardboard has thickness (fluting from 1.5mm up to 7mm). Designing based on external measurements will result in a box that is too small for your product!
- External Dimensions (Crucial for Courier Shipping): Measures the outside footprint including board thickness. Couriers use external dimensions to calculate volumetric (dimensional) weight for postage costs.
### 2. Internal vs. External Dimensions:
### 3. Step-by-Step Measurement Guide:
1. Measure Your Product: Place the item on a table and measure its maximum outer bounds (L × W × H) including caps, cords, or protruding parts.
2. Add Clearance Tolerances:
- Snug Fit (Folding cartons): Add 2mm–3mm to each dimension for easy product loading.
- Mailer Boxes & E-commerce: Add 5mm–10mm per side to allow space for tissue paper, void fill, or inserts.
3. Specify Board Caliper: Let your packaging supplier know your internal requirements so they can calculate the exact dieline score lines based on board thickness.