Reverse Dimensional & Cubic Weight Box Calculator
Enter your target chargeable weight and two fixed carton sides (Length × Width) to calculate the exact maximum box height before crossing into the next US, UK/EU, Australian, or Canadian carrier billing bracket.
1. Target Weight & Fixed Footprint
2. Maximum Allowed Box Geometry
Need this exact box size? Order custom-cut RSC or mailer cartons with zero dead air.
Quote Custom Box →Common Stock Carton Comparison Against Your Target
Standard off-the-shelf shipping cartons evaluated under your selected divisor. Green rows fit within your target chargeable weight.
| Stock Carton (L × W × H) | Cubic Volume | Raw Volumetric / Cubic Wt | Billable Weight | Status vs. Target |
|---|
How Reverse Dimensional & Cubic Weight Sizing Works
Standard calculators force you to guess box dimensions and discover surcharges afterward. Reverse sizing flips the formula so you engineer packaging around carrier thresholds from the start:
Max Volume = Target Billable Weight × Carrier Divisor
Max Height = Max Volume ÷ (Length × Width)
Regional Divisors & Laser Dimensioner Buffers
In Australia, carriers calculate cubic weight at 250 kg/m³ (equivalent to dividing cm³ by 4,000), whereas UK, European, and Canadian express networks divide cm³ by 5,000, and US parcel networks divide in³ by 139. Because automated conveyor scanners measure outer tape bulge, always subtract a 0.25 in (6 mm) tolerance when ordering custom cartons.