A customer brings in two boxes. One is packed with books and weighs 38 lbs. The other is stuffed with pillows and comforters and weighs 11 lbs. The light one costs more to ship. Why? Because the pillows and comforters went into an XL box, while the books were in a medium. This surprises somebody every week, and the reason is always the same: carriers don’t charge for weight alone.
What Is Volumetric Weight?
Carriers charge on actual weight or volumetric weight – whichever is higher. Volumetric weight, also called dimensional or DIM weight, measures the space a box takes up rather than what’s inside it.
The logic is simple. A plane or a truck runs out of room long before it runs out of weight capacity, and a box of pillows takes up exactly as much space as a box of bricks. If carriers billed by the scale alone, they’d lose money on every large, light shipment they carried.
How It’s Calculated
Multiply length × width × height in inches, then divide by the carrier’s dimensional divisor. 139 is a common one.
- A 20 × 20 × 20-inch box = 8,000 cubic inches
- 8,000 ÷ 139 = 58 lbs volumetric weight
If that box weighs 12 lbs on the scale, you’re billed as if it weighs 58. The divisor changes by carrier and by service, so it’s worth confirming the current one before pricing anything.
What Triggers It Most Often
- Bedding, pillows, comforters, and towels
- Winter coats and bulk clothing
- Lampshades and light fixtures
- Empty coolers, luggage, and storage bins
- Gift baskets and oversized gift boxes
- Sports equipment
- Anything shipped in a box much bigger than the item itself
How to Keep It From Costing You
- Right-size the box – a few extra inches on every side adds real billed weight.
- Fewer, denser boxes usually beat more, emptier ones.
- Compress soft goods – bedding and clothing pack down a lot before they go in the box.
- Skip the empty air – cushion fragile items where they need it, not with a bigger box.
- Measure before you price – dimensions matter as much as the number on the scale.
Where It Hurts Most
This applies to every shipment, domestic or international. But the dollar impact is far bigger overseas, where the rate per pound starts out higher and one badly packed box gets multiplied across a whole shipment.
It’s also why volumetric weight decides which international shipping option is the best route for you. A bulky, light shipment can cross the 100 lb bulk thresholds on dimensions alone, even though the scale says otherwise – which changes the options on the table. Those options are compared in “Bulk International Shipping Compared: Direct Carrier Pricing, Package Aggregators, and Freight.“
Not Sure If Your Box Is Costing You Extra?
Bring the box in, or send us its weight and dimensions. We’ll calculate both numbers and tell you whether repacking would save you more than the materials cost. Goin’ Postal Madison, 7169 Highway 72 W Ste A, Madison, AL 35758. Call (256) 258-7706.
Frequently Asked Questions
- What is volumetric weight in international shipping?
It measures the space a package takes up. Carriers charge based on actual weight or volumetric weight, whichever is higher.
- Do all carriers use it?
Yes, on both domestic and international shipments. The divisor they use differs by carrier and service.
- Does it apply to ground shipping?
Yes. It isn’t an air-only rule.
- How do I calculate it myself?
Length times width times height in inches, divided by the carrier’s divisor. Compare that to the actual weight – the higher number is what you’re billed.
- Does volumetric weight affect bulk international shipments too?
Yes, on all three routes – direct carrier bulk pricing, package aggregators, and freight. A bulky shipment can be billed at a much higher weight than the scale shows, which is why we measure before quoting.
Read next in this series
- Bulk International Shipping in Madison, AL & Huntsville, AL: How to Ship Big Without Paying a Fortune
- Bulk International Shipping Compared: Direct Carrier Pricing, Package Aggregators, and Freight