Box Size Optimizer
Find the best standard shipping box for your product and minimize wasted space.
Product Dimensions
Number of units in one box
Void fill allowance each side
Choosing the Right Box Size
Picking the right box size impacts your shipping costs in two ways: actual weight and dimensional weight (DIM weight). Carriers charge whichever is greater. Oversized boxes inflate your DIM weight and waste void fill material.
- Best fit = the smallest standard box that fits your product with padding. This minimizes DIM weight and void fill cost.
- DIM weight is calculated as: (L × W × H) ÷ 139 for UPS/FedEx domestic. The divisor varies by carrier and shipment type.
- 2 inches of padding on each side is typical for fragile items. Reduce to 1" for durable items in mailers.
- Standard cubic boxes (12×12×12) are ideal for near-cubic products — they have good stackability and low wasted space.
Standard box sizes listed here are common USPS, UPS, and FedEx-compatible corrugated sizes. Your actual supplier may offer slightly different dimensions — always verify before ordering in bulk.