Most shipping boxes carry a lot of air. One mug in a box built for four, a phone case rattling around in a shoe box, a cushion of crumpled paper that takes up more room than the product. Carriers already charge you for that air through dimensional weight. In the EU, there is now also a legal limit on how much of it a box may contain.

This guide explains what the rule says, what counts as empty space, how to measure it for your own parcels, and how to bring the number down.

What the EU rule says

The rule comes from the EU Packaging and Packaging Waste Regulation, Regulation (EU) 2025/40, usually shortened to PPWR. Its Article 24 sets a maximum empty space ratio of 50% for three kinds of packaging:

  • grouped packaging (several sales units packed together),
  • transport packaging,
  • e-commerce packaging (the box an online order is shipped in).

The obligation sits with the business that fills the packaging, which for an online shop usually means whoever packs the order.

Two dates matter:

  • The European Commission has to adopt the official calculation method by 12 February 2028, as an implementing act.
  • The 50% cap applies from 1 January 2030, or three years after that method enters into force, whichever comes later. If the Commission is late, the start date moves back too.

You may have seen a 40% figure or an August 2026 deadline in older articles. The 40% figure came from earlier drafts of the regulation, and the final text uses 50%. August 2026 is when most of the regulation starts to apply, but the empty-space cap itself is tied to the 2030 date.

The regulation also has specific exceptions and details that matter for particular product types. If you are planning compliance work, read Article 24 in the official text on EUR-Lex rather than relying on a summary, including this one.

What counts as empty space

Empty space is the part of the box that is not product. In practice:

  • Filler counts as empty space. Paper, air cushions, bubble wrap, foam and loose fill do not make the box any less empty. You cannot pass the test by stuffing more paper in.
  • The space between items counts. If two products leave a gap between them, that gap is empty space whether you fill it or not.
  • The padding around the whole load counts. The margin you leave between the products and the box walls is empty space too.

That last point surprises people. A box that looks perfectly full can still be a third empty once you account for the padding.

How to measure it yourself

The idea is simple:

empty space ratio = (box volume - product volume) / box volume

A worked example:

  • Box: 40 × 30 × 30 cm = 36,000 cm³ (36 L)
  • Products: a 30 × 20 × 12 cm shoe box and two 12 × 10 × 10 cm mug boxes = 7,200 + 2,400 = 9,600 cm³ (9.6 L)
  • Empty space: 36,000 - 9,600 = 26,400 cm³, so the ratio is 26,400 / 36,000 = 73%

That box would be well over the limit. Repacking the same three items into a 33 × 23 × 25 cm box gives a ratio of about 49%.

Two caveats until the official method is published:

  • Use the inner volume of the box when you can. Summaries of the rule describe the ratio against the inside of the packaging. Outer dimensions overstate the box volume slightly because of the cardboard thickness.
  • Irregular products are harder. For a bottle or a lamp, the "product volume" depends on how the method treats non-rectangular shapes. Until the Commission publishes it, treat any number you calculate as an estimate.
Try the tool →

Why small boxes struggle

Padding hurts small boxes far more than big ones. Take items that fill a 20 × 15 × 24 cm block perfectly and add 3 cm of padding to each dimension:

  • Box: 23 × 18 × 27 cm = 11,178 cm³
  • Products: 20 × 15 × 24 cm = 7,200 cm³
  • Empty space: 36%, with zero gaps between the items

The same 3 cm of padding around a 60 × 40 × 40 cm load adds only about 18% empty space, because padding grows with the surface of the box while the products grow with its volume. If you ship small items, padding is the first thing to look at.

How to cut empty space

  1. Size the box to the order, not the other way around. Calculate the smallest box that fits the actual items, then pick the closest stock size above it.
  2. Rotate items. The same products can need a very different box depending on whether they lie flat, stand on edge or sit side by side. Test the orientations before choosing a size.
  3. Fill gaps with products, not paper. If an order has a small item, put it in the gap next to a bigger one instead of padding that gap with filler.
  4. Use only the padding the product needs. Soft goods rarely need more than 1 cm on each side. Save thick padding for fragile items, and wrap fragile items individually instead of padding the whole box.
  5. Keep more than one box size. Two or three well-chosen sizes usually cover most orders with far less air than one universal box.

Check your own boxes

The 3D Box Packing Calculator does the measuring for you:

  • In Calculate box mode it finds the smallest box for your items and shows how they fit in 3D.
  • In Check your box mode you enter a box you already use and see whether everything fits and how much of it stays empty.
  • The Empty space panel splits the percentage into box padding, wrap around each item and real gaps between items, with a marker at 50%.
  • Gaps for filler lists every empty spot with its exact size, so you know what is left to fill.
  • You can drag boxes around in the 3D view to try other arrangements, and set padding for the whole box separately from wrap around each item.

Everything runs in your browser, with no sign-up required.

The percentage in the calculator is an estimate based on the dimensions you enter. It is not a compliance check, and the official calculation method is still to come. For legal decisions, rely on the regulation itself and, where needed, professional advice.

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