Complete Shipping Box Size Chart for Safe Deliveries

A shipping box size chart with top sizes, shipper limits. Dim-weight math so your parcels ship safe and cheap across USPS, UPS, and FedEx. At Discount Box Printing, we make custom packaging boxes to any size, factory-direct across the United States. This guide covers sizes, tips. Cost points so you pick right the first time.

• Small parcel: 12 × 9 × 4 in
• Medium parcel: 16 × 12 × 8 in
• Large parcel: 20 × 16 × 12 in
• USPS length cap: 108 in
• UPS/FedEx L+girth cap: 165 in
• Dim divisor: 139 (USPS/UPS/FedEx retail)
• Wall grade: single-wall to 65 lb, double past that
• Turnaround: 10–12 business days

How to Read a Shipping Box Size

Every shipping box is spec\u2019d as three numbers: length by width by height. Length is the long side of the opening. Width is the short side. Height is the depth. So a 12 × 9 × 4 shipper is 12 long, 9 wide, and 4 deep. Use inside sizes so the item fits with a pad.

top Shipping Box Sizes

Most orders fit in three sizes. A 12 × 9 × 4 handles books, small kits, and cosmetic sets. A 16 × 12 × 8 fits a full subscription box or a rolled pair of shoes. A 20 × 16 × 12 wraps around big electronics, small appliances. Five to seven t-shirts. Browse our custom corrugated boxes for wall grades and prints.

shipper Size and Weight Limits

USPS Ground Advantage caps parcels at 108 in length and 130 in for length plus girth, at 70 lb. UPS and FedEx ground both cap length at 108 in and length plus girth at 165 in, at 150 lb. Oversize fees kick in past 96 in of length. See USPS size limits for the latest.

Dim Weight Math That Sets Your Price

shippers bill on the higher of actual weight or dim weight. Dim weight = (L × W × H) / 139. A 16 × 12 × 8 box has a dim of 11 lb. If your kit weighs 4 lb, you still pay for 11 lb. So a smaller box cuts shipping more than lighter contents.

Wall Grade for the Load Inside

Single-wall 32 ECT handles up to 65 lb and most e-com loads. Double-wall 44 ECT handles 65 to 100 lb and drop-shipped bulky items. Triple-wall covers 100 lb and up for pallet-adjacent freight. Match the wall to the load and add a 15 percent safety cushion.

Picking the Right Size for Your item

Measure the item at its widest, tallest, and deepest points. Add 1/4 to 1 inch per side for a pad, wrap, or air pillow. Match the total to the nearest stock size or spec a custom box at the exact numbers. Two or three sizes cover most SKU lines cheaper than one giant catch-all box.

Common Shipping Mistakes to Avoid

Using an oversized box and paying for empty space. Skipping the pad and taking a return. Sizing to outside dims and losing 1/2 in inside. Ignoring the girth cap on long thin items. Using single-wall for a 50 lb load. Each one costs more than the box itself.

Sizes & Dimensions Chart

top shipping carton sizes with the wall grade shippers charge best on.

Wholesale Cost and Ordering

Custom sizes cost the same as stock sizes in bulk. So there is no reason to force an item into a poor fit. We make the boxes ourselves. Means no reseller markup and no setup fee. Low MOQs let you test a size before you scale. Send a rival quote through Beat My Quote and we will try to come in lower.

1. Request a free quote. Share the size, the style, the print, and the count.
2. Get a free proof. Our team preps a dieline and a 3D mockup at no cost.
3. Approve and we print. We build factory-direct after sign-off.
4. Free US delivery. Your boxes ship to your door in 10 to 12 days.

Explore More

• top Packaging Box Dimensions — sizes by field.
• Corrugated Box Dimensions — heavy-duty wall grades.
• Mailer Box Dimensions — e-commerce shipper sizes.
• Ecommerce Packaging Dimensions — online-store sizing.
• How to Measure Packaging Dimensions — measuring 101.