Best Pick
⚠ DIM +30 lb100% Perfect fitGRAINGER APPROVED 11A776 PK 20 Shipping Box,18x18x16 in 11A776
18″ × 18″ × 16″
+$9.99 Seller Calculated · 32 lb billed
$2.32
landed per box
$1.82 each
pack of 20 · $36.40
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Cheapest 18×18×16 padded mailer
Compare real eBay prices for 18×18×16 shipping boxes with DIM-weight-aware shipping estimates.
Live listings — sorted by landed cost per box
⚠ DIM +30 lb100% Perfect fitBuy →
⚠ DIM +30 lb100% Perfect fitUOFFICE Corrugated Boxes 18 x 18 x 16" Pack of 20 Shipping Cartons
18″ × 18″ × 16″
+$0.00 Seller Free shipping · 32 lb billed
$2.60
landed per box
pack of 20 · $52.00
⚠ DIM +311 lb70% Good fit30 Pack Medium Moving Boxes with Handles-18”1/18 X 18” X 16”
180.05555555555554″ × 18″ × 16″
+$0.00 Seller Free shipping · 313 lb billed
$2.68
landed per box
$2.33 each
pack of 30 · $69.90
⚠ DIM +30 lb100% Perfect fitUOFFICE Corrugated Boxes 18 x 18 x 16" Pack of 20 Shipping Cartons
18″ × 18″ × 16″
+$0.00 Seller Free shipping · 32 lb billed
$2.73
landed per box
pack of 20 · $54.60
⚠ DIM +30 lb100% Perfect fitGRAINGER APPROVED 55NM87 PK 20 Shipping Box,18x18x16 in 55NM87
18″ × 18″ × 16″
+$9.99 Seller Calculated · 32 lb billed
$3.04
landed per box
$2.54 each
pack of 20 · $50.80
⚠ DIM +34 lb96% Perfect fit18x18x18 Corrugated Shipping Boxes 25/pk
18″ × 18″ × 18″
+$0.00 Seller Free shipping · 36 lb billed
$3.24
landed per box
$3.18 each
pack of 25 · $79.50
Showing 6 of 17 real listings. Want all of them with custom quantity and weight? Search now →
What fits in a 18×18×16 box
A 18 × 18 × 16 inch box holds 5,184 cubic inches (3.00 cu ft) of interior space, putting it in the extra-large-cube category. It's a popular choice for shipping items like moving boxes, appliances, bulk household shipping — things that fit comfortably within those dimensions while leaving room for protective padding. Large boxes at this size are usually sold in smaller bulk packs — 10 to 25 — because storage and shipping of the empty stock itself becomes a consideration.
Shipping math for this size
Shipping cost for this size depends heavily on dimensional weight. For a 18×18×16 box, UPS and FedEx Ground compute a DIM weight of 38 lbs using their 139 divisor, while USPS Ground Advantage uses a 166 divisor, giving 32 lbs. Carriers bill whichever is greater — your actual weight or the DIM weight. USPS's higher divisor makes it roughly 6 lbs cheaper than UPS/FedEx for this size when your item is light, which is why our search results factor in DIM-weight automatically instead of just showing sticker prices.
How to pick the right pack size
When buying a 18×18×16 box, the biggest cost lever isn't which retailer you pick — it's which pack size you commit to. A 100-pack typically costs 2-3× more than a 25-pack but brings the per-unit cost down by 40-60%. Our ranking is based on **landed cost per box** — the pack price plus shipping, divided by the number of boxes. A 100-pack with $10 shipping works out cheaper per box than a 25-pack with the same shipping, because the fixed cost spreads further. Every listing below links to a real product page from eBay, ULINE, or other retailers; we don't show placeholder results.
Search with your own dimensions
Pre-filled with 18×18×16. Adjust weight, quantity, or size as needed — we'll re-rank for your exact scenario.