What void fill is for
Void fill is the material used to occupy empty space in a box. Its main job is to stop the contents moving, because movement is what turns a small knock into damage. Its second job is to absorb some shock. It is not a substitute for a well-sized box, and it works best when paired with sensible sizing and, for delicate goods, an inner layer of wrapping directly around the product.
The common choices are paper, air pillows and foam, with several variants of each. No option wins on every measure, so the right one depends on what you ship.
Paper
Paper fill comes as crumpled kraft sheets, shredded paper or honeycomb-style expanding paper.
Strengths
- Widely accepted in household paper recycling in many areas.
- Good at blocking, bracing and holding items in place.
- Feels natural to customers, which suits many brands.
- Can be made on demand from rolls, with compact storage.
Weaknesses
- Usually heavier than air pillows for the same volume, which adds a little weight to each parcel.
- Compresses under load, so it can lose cushioning over a long journey.
- Packing is slower when done by hand, and it needs training to give consistent results.
- Paper dust may be a concern for some electronics or cleanroom goods.
Best for: sturdy items, mixed orders, and cases where recyclability and presentation matter.
Air pillows
Air pillows are sealed plastic cushions inflated by a machine from flat film, or supplied pre-inflated.
Strengths
- Very light, so they add almost nothing to parcel weight.
- Fast to use once the machine is set up, and consistent results.
- Good volume fill at low cost per parcel.
- Film is stored flat, taking little space until inflated.
Weaknesses
- Offer limited shock absorption and tend to be better at filling space than cushioning heavy items.
- A puncture deflates one pillow, though the others stay inflated.
- Need a machine and power if inflated on site, and the film must be kept supplied.
- Pre-inflated pillows take up a lot of storage room.
- The plastic is not accepted in all household recycling, although some collection schemes take clean plastic film. Customers may find disposal inconvenient.
Best for: light to moderate items in appropriately sized boxes, where weight and speed matter.
Foam
Foam covers several formats: loose-fill foam pieces (often called peanuts), foam sheets, molded or cut inserts and foam-in-place systems where liquid expands around the product.
Strengths
- Strong cushioning and shock absorption, particularly molded or custom-cut inserts.
- Holds products precisely in position, which suits suspension packing.
- Light for the protection it provides.
- Resists moisture better than paper.
Weaknesses
- Tends to be the most expensive per parcel, especially custom shapes.
- Many foams are difficult to recycle and often end up in general waste, though some starch-based loose fill dissolves in water and some schemes accept foam.
- Loose-fill pieces can be messy and may cause static.
- Molded inserts need design work, minimum quantities and storage space.
Best for: high-value, fragile or oddly shaped products, electronics and repeat shipments of the same item.
Side-by-side comparison
| Factor | Paper | Air pillows | Foam |
|---|---|---|---|
| Blocking and bracing | Good | Fair | Very good (shaped) |
| Shock absorption | Moderate | Low to moderate | High |
| Added weight | Higher | Very low | Low |
| Storage before use | Moderate (rolls are compact) | Very low if flat film | Moderate to high |
| Typical cost per parcel | Low to moderate | Low | Moderate to high |
| Customer disposal | Often easy | Can be harder | Often hardest |
| Speed of packing | Slower by hand | Fast | Varies by format |
These are general tendencies. Actual performance depends on the specific product, how much material is used and how it is placed.
Other options
Some sellers use corrugated inserts, molded pulp trays, bubble film or fabric wraps as additional or alternative protection. Bubble film is good for wrapping single items directly. Corrugated and pulp inserts are recyclable and make strong dividers. Some systems return and reuse cushioning, which links to the broader topic of reusable packaging.
How to choose
Ask these questions in order:
- How fragile and valuable is the product? More delicate goods need foam or layered cushioning, possibly with a second box.
- How heavy is it? Heavy items need firm support that does not collapse. Air pillows may fail on the bottom of a heavy load.
- How is it shaped? Odd shapes may need custom support, while regular shapes can be braced with paper.
- What are the weight and volume rules? Light fill can help if you are near a weight bracket, but only if the box is correctly sized.
- What happens after delivery? Consider what your customers can easily recycle or reuse, and your own waste handling.
- How many parcels do you ship? A machine for air pillows or foam-in-place pays off with steady volume, while paper may suit smaller operations.
Using fill well
- Fill the box so the contents cannot move, but do not pack so tightly that the lid bulges.
- Put a layer of fill under and over the product, as well as around it.
- Shake the box after packing and add more if anything shifts.
- Do not use void fill to correct a box that is much too large. A smaller box usually saves more material and cost, and reduces the volume that carriers charge on.
If you are unsure which material suits a product, try a small batch with each, then compare damage rates and costs. Simple testing gives a better answer than assumptions.