Best Pick
eBay Brand Central12" x 15" Polyjacket/Polymailer — 400 Envelopes
12″ × 15″ × 0″
+$0.00 Seller Free shipping · 3 lb billed
$0.230
landed per box
pack of 400 · $92.00
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⚠ DIM +12 lb92% Perfect fitBuy →
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Cheapest 12×12×12 padded mailer
Compare real eBay prices for 12×12×12 shipping boxes with DIM-weight-aware shipping estimates.
Live listings — sorted by landed cost per box
eBay Brand CentralBuy →
eBay Brand Central14.5" x 18.5" Polyjacket/Polymailer — 400 Envelopes
14.5″ × 18.5″ × 0″
+$0.00 Seller Free shipping · 3 lb billed
$0.290
landed per box
pack of 400 · $116.00
⚠ DIM +12 lb92% Perfect fitGRAINGER APPROVED 11A738 PK 25 Shipping Box,16x12x12 in 11A738
16″ × 12″ × 12″
+$9.99 Seller Calculated · 14 lb billed
$1.53
landed per box
$1.07 each
pack of 25 · $26.75
⚠ DIM +9 lb100% Perfect fit50 12x12x12 Cardboard Paper Boxes Mailing Packing Shipping Box Corrugated
12″ × 12″ × 12″
+$0.00 Seller Free shipping · 11 lb billed
$1.56
landed per box
pack of 50 · $78.00
⚠ DIM +9 lb100% Perfect fit12x12x12 Corrugated Shipping Boxes 50/pk - The Boxery
12″ × 12″ × 12″
+$0.00 Seller Free shipping · 11 lb billed
$1.57
landed per box
pack of 50 · $78.50
⚠ DIM +9 lb100% Perfect fit12x12x12 Corrugated Shipping Boxes 25/pk - The Boxery
12″ × 12″ × 12″
+$0.00 Seller Free shipping · 11 lb billed
$1.58
landed per box
pack of 25 · $39.50
Showing 6 of 26 real listings. Want all of them with custom quantity and weight? Search now →
What fits in a 12×12×12 box
A 12 × 12 × 12 inch box holds 1,728 cubic inches (1.00 cu ft) of interior space, putting it in the large-cube category. It's a popular choice for shipping items like kitchen appliances, speakers, multiple books — 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 12×12×12 box, UPS and FedEx Ground compute a DIM weight of 13 lbs using their 139 divisor, while USPS Ground Advantage uses a 166 divisor, giving 11 lbs. Carriers bill whichever is greater — your actual weight or the DIM weight. USPS's higher divisor makes it roughly 2 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 12×12×12 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 12×12×12. Adjust weight, quantity, or size as needed — we'll re-rank for your exact scenario.