Shipping size planner
Box Size and Dimensional Weight Calculator
Calculate box volume, dimensional weight, and billable shipping weight so your packaging does not create avoidable freight cost. Use it for mailer boxes, shipping boxes, subscription boxes, and ecommerce packaging.
Right-size the box
Reducing unused internal space can lower freight cost and reduce void fill.
Protect the product
Fragile products may need inserts or corrugated board even when a smaller carton fits.
Related pages
Review mailer boxes, corrugated boxes, custom printed boxes, and ecommerce packaging guides.
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Questions Buyers Ask
What is dimensional weight?
Dimensional weight estimates shipping weight from package size. Carriers compare it with actual weight and usually bill the higher number.
Which dimensional divisor should I use?
Many US parcel calculations use 139 for retail-style rates and 166 for some negotiated or economy lanes. Always confirm with your carrier.
How much clearance should I add around a product?
Start with 0.25 to 0.5 inches per side for small products, then increase for fragile items, inserts, or protective void fill.