Dimensional Weight (DIM Weight)
Carriers like UPS and FedEx don't just charge by weight. They charge by size too. Ship something light in a big box and they'll bill you as if it weighs way more than it does. This catches a lot of merchants off guard.
Example
Your product weighs 2 lbs but ships in an 18×14×10 box. The carrier calculates dimensional weight as 15 lbs. You get charged for 15 lbs — 7.5 times the actual weight. That $6 shipment you budgeted just became $12
Why It Matters
Carriers charge by dimensional weight — the size of the box, not just the actual weight. Merchants who use oversized boxes pay 30-50% more than necessary for every shipment. This is one of the easiest margin leaks to fix.
Pro Tip
Measure your top 5 shipped products and find the minimum box size for each. A $0.50 smaller box can save $2-3 per shipment.
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