Find the smallest box that fits your order items and calculate void fill percentage. Reduce shipping costs and packaging waste with right-sized cartons.
Cartonization is the process of selecting the smallest possible shipping box that safely contains all items in an order. Oversized boxes waste money in three ways: higher dimensional weight charges from carriers, more void fill material required, and increased transportation cost from fewer boxes fitting on a truck.
This calculator compares the total volume of items in an order against available box sizes to identify the best fit. It calculates the void fill percentage — how much of the box is empty space — and flags when a smaller box could be used. Industry best practice targets less than 30% void fill, with top performers achieving under 15%.
Use this tool to evaluate your current box assortment, justify investment in additional box sizes, or build the case for auto-boxing technology that creates custom-fitted cartons for every order.
Supply-chain managers, warehouse operators, and shipping coordinators rely on precise cartonization data to maintain efficiency and control costs across complex distribution networks. Revisit this calculator whenever conditions change to keep your logistics plans aligned with real-world performance.
Carrier dim weight charges mean you pay for the box size, not just the product weight. A box that is 20% too large can cost 20% more in shipping. This calculator quantifies void fill so you can see the waste and select the right box size. Across thousands of daily shipments, even small improvements pay for themselves quickly.
Box Volume = Box Length × Box Width × Box Height Void Fill % = ((Box Volume − Item Volume) / Box Volume) × 100 Cubic Efficiency % = (Item Volume / Box Volume) × 100
Result: 28.6% void fill (71.4% cubic efficiency)
Box Volume = 14 × 10 × 8 = 1,120 cu in. Void = ((1,120 − 800) / 1,120) × 100 = 28.6%. This is within the 30% target. A 12×10×8 box (960 cu in) would reduce void to 16.7% and save material and dim weight charges.
An oversized box costs more in three ways: higher dim weight shipping charges, more void fill material, and wasted trailer space. A study by Packsize found that the average ecommerce shipment has 40% void fill, costing the industry billions annually in wasted material and shipping surcharges.
Analyze your order data to cluster item dimensions and identify the 6-8 box sizes that best cover your range. Start with the most common item combinations and work outward. Reassess quarterly as product mix changes.
WMS cartonization algorithms analyze order items and recommend the best box size in real time. Advanced systems consider item fragility, orientation requirements, and weight distribution. Auto-boxing machines go further by creating custom boxes, achieving near-zero void fill for every order.
Under 30% is the standard target. High-performing operations achieve 10-20%. Above 40% strongly indicates an oversized box is being used and should be replaced with a smaller size.
Most operations need 5-10 standard sizes to achieve good cartonization across their product range. Too few sizes (under 4) creates excessive void. Too many (over 15) adds storage, inventory, and handling complexity.
Dimensional weight is a shipping pricing method that reflects package density. It is calculated as (L × W × H) / dim factor (typically 139 for US domestic). Carriers charge the greater of actual weight or dim weight.
Proper cartonization reduces dim weight charges (smaller boxes = lower dim weight), saves dunnage material, fits more packages per truck (reducing freight cost), and reduces damage from items shifting in oversized boxes. Consult a professional for advice tailored to your specific situation.
Auto-boxing machines measure items and create custom-fitted corrugated boxes in real time. They eliminate the need for standard box sizes and virtually eliminate void fill. They typically cost $200K-$500K and handle 500-1,500 boxes per hour.
Void fill percentage is calculated before dunnage. Dunnage fills the void to protect products. The goal is to minimize the void so less dunnage is needed. If void fill is under 15%, some products may not need dunnage at all.