Volumetric Weight Explained: How Courier Companies Calculate Shipping Charges

One of the most common billing surprises for new e-commerce sellers is discovering that a lightweight package was charged as if it weighed several kilograms more. The reason: volumetric weight.

The Formula

Couriers charge based on whichever is greater — the actual physical weight or the calculated volumetric weight. The divisor (usually 5000 for domestic, sometimes 4000–6000 depending on the courier) reflects how much space a shipment occupies relative to its weight.

A Practical Example

Consider a box measuring 40cm × 30cm × 20cm with an actual weight of 1kg. The volumetric weight is (40 × 30 × 20) ÷ 5000 = 4.8kg. Even though the parcel physically weighs just 1kg, the courier will bill it as 4.8kg — nearly five times higher.

Why This Matters Most For Certain Categories

• Apparel: Loosely packed clothing takes up more box volume than its weight suggests
• Cosmetics and Beauty: Small items often shipped in oversized boxes with excess void fill
• Electronics: Protective packaging can significantly inflate dimensions
• Home Décor: Naturally bulky, low-density items are the most exposed to volumetric charges

How to Minimise Volumetric Weight Charges

• Choose the smallest box that safely fits the product
• Avoid excess void-fill material; use appropriately sized cushioning instead
• Use flat or slim packaging for apparel wherever possible
• Regularly audit your top SKUs' actual vs volumetric weight to catch inefficient packaging

For high-volume sellers, even a small reduction in package dimensions per shipment compounds into significant savings across thousands of orders per month.