Box Resizer
Got a box that's close but too big? Enter your box and item dimensions — we'll show you how to modify the box to save on DIM weight shipping costs. Two techniques, zero waste.
Your box
Your item
Original box
12×12×12
$29.50
USPS · 11 lb billed
This box is already a good fit — no modification needed.
Method 1: Score down (reduce height)
The simplest modification. Mark the new height on all four walls, score a fold line with a straightedge and box cutter, trim the flaps to the new height, fold and tape. Takes 2 minutes and requires only a box cutter and tape. The tradeoff: you waste the trimmed flap material, and you can only reduce height — length and width stay the same.
Method 2: Easy Reshape (zero waste)
The easiest technique. Open the flaps and make vertical cuts on each flap at the desired width — from the flap edge to the fold crease, near each corner. Top and bottom. Then fold the walls inward. The folded wall extends the box length while narrowing the width. Zero waste, clean result, works on any corrugated box.
Why does this save money?
Carriers (UPS, FedEx, USPS Ground) charge based on dimensional weight: L × W × H ÷ 139 for domestic US. A 12×12×12 box has a DIM weight of ~12.4 lb — even if your item only weighs 3 lb, you're billed for 13 lb. Reshape that same box to 12×6×18 and the DIM weight drops to ~9.4 lb. Same cardboard, same item, lower shipping bill.