How to reduce void space in shipping boxes: 7 tips for the 40% limit
The PPWR allows a maximum of 40% empty space in shipping boxes. These seven measures get your packaging under the limit — and save postage at the same time.
Why cutting void space pays off twice
The EU Packaging Regulation (PPWR) caps empty space in shipping, grouped and transport packaging at 40%. That is not just compliance but real money: every centimetre of air in the box costs postage, filling material and licensing fees. The following seven measures reduce void space systematically. You can calculate your exact ratio anytime with the PPWR void-space calculator.
The 7 measures
- Tier your box range: keep several sizes rather than forcing everything into a few universal boxes — the most effective lever.
- Optimise top sellers first: match your top items and typical baskets to suitable boxes.
- Use height-adjustable boxes: boxes with fold lines or adjustable lids adapt to the product.
- Use filling material in a targeted way: ensure protection without inflating volume — void space counts despite padding.
- Bundle products sensibly: arrange multiple items compactly instead of over-packing each one.
- Embed pick-and-pack rules: give the warehouse clear guidance on which box size to choose when.
- Document the result: file the void-space ratio per standard box as an audit PDF — as evidence of packaging minimisation.
How to check the limit
The void-space ratio is (1 − product volume ÷ box volume) × 100. What that means in detail and why 40% is the limit is explained in The PPWR void-space limit explained. How to determine the right box size is shown in the guide Calculate shipping box size.
The fastest way to start
Take your five most-shipped products, measure the product and the current box, and check the ratio in the void-space calculator. If it is above 40%, the tool recommends a concrete smaller box height. Often a single additional flatter box size is enough to make most shipments compliant.
Frequently asked questions
How much void space is allowed in the box?
Under the PPWR, a maximum of 40% in shipping, grouped and transport packaging — at least 60% of the box volume must be used by the product and any necessary protective material.
Does filling material count against void space?
What matters is packaging minimisation: the goal is a box with as little void space as possible. Over-filling with padding does not replace the right box size and causes additional cost and waste.
What is the easiest way to meet the 40% limit?
A tiered box range. Keeping suitable boxes for different product sizes is the most reliable way to stay within the limit across your whole range. Height-adjustable boxes reduce the number of sizes needed.
How do I prove compliance?
Calculate the void-space ratio for each box–product combination and save the result. The PPWR void-space calculator produces an audit PDF with the calculation, timestamp and result for your compliance records.
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