Packaging resources

Packaging Insert Guide

Board, foam and moulded pulp inserts compared, with cavity tolerances, multi-piece layout guidance and when an insert is not needed at all.

The Retail Packaging editorial team Updated August 11, 2026 4 min read
Rigid box with a fitted insert holding components in separate cavities

Most transit damage happens because the product moved inside a box that survived. An insert stops that movement, and it is usually the cheapest reliability improvement in a specification.

Material comparison

Material Protection Cost Presentation Recyclable
Corrugated Immobilises well, absorbs poorly Low Fair Yes, with the box
Chipboard Light restraint only Low Good in shallow trays Yes
Moulded pulp Good impact absorption Medium Poor surface Yes
PU foam Excellent absorption Medium-high Very good No
EVA foam Excellent, clean cut edge High Excellent No

Board handles most products up to moderate weight. Foam is for anything genuinely fragile — glass, ceramics, unprotected screens. Moulded pulp sits between the two but cannot be a visible presentation layer.

Cavity tolerance

A cavity cut to exact product dimensions will not accept the product. Manufacturing variance in both means an exact fit binds.

Allow 1 mm to 2 mm clearance around the product for board inserts, slightly less for foam, which compresses. Softer products tolerate tighter cavities than rigid ones.

Always include a finger relief cut. A cavity that grips well enough to protect in transit is one the customer cannot get the product out of.

Multi-piece layout

Decide what the customer should see first and give it the most prominent position. Group accessories logically rather than by what packs most efficiently. Give cables and small parts their own compartment.

Layered inserts suit products with a clear hierarchy — main item on top, accessories beneath. Each layer needs its own removal relief.

When you do not need one

Soft goods rarely need internal structure; a folded garment cushions itself. Products that fill the outer pack completely have nowhere to move. Single hard-wearing items usually travel fine in a snug outer alone.

Right-sizing the outer box is frequently a better answer than adding structure inside an oversized one, and it reduces dimensional weight at the same time.

Specifying correctly

An insert is cut to the inside of the outer pack, not to the product alone, so both sets of dimensions are needed. Send the exact measurements and weight of every item requiring a cavity, and flag which are fragile.

Where items of very different weights sit together, say so — a heavy item shifting beside a light one is a common damage mode.

Testing

Order a plain sample of insert and outer together, load it with the real product and drop it from about a metre onto a hard floor on several faces.

If the product shifts, tighten the cavity. If the insert deforms, step up the material. If the outer creases at a corner, load is not being distributed and the geometry needs work. Our guide to measuring products and allowing clearance covers the dimension side of the same problem.

Transit fit and presentation fit are different jobs

An insert that grips a product firmly for transit is usually invisible and slightly tight. An insert that presents a product on opening seats it loosely and is part of what the recipient sees. Asking one part to do both tends to compromise one of them.

Decide which matters more before anything is cut. Where both genuinely matter — premium electronics, fragrance, gift sets — the answer is normally a presentation layer inside a protective outer rather than one clever component trying to do everything.

Reading a damage report

Damage patterns point directly at the fix, and misreading them is what produces expensive changes that do not work.

What arrives What it means What to change
Box crushed, contents intact Board too light for the stack Heavier flute, or better palletisation
Box intact, contents damaged Product moved inside Fitted insert
Corner crushed, contents fine Impact on a drop Corner protection or a deeper insert
Contents scuffed, nothing broken Product rubbing the cavity Softer cavity face or a liner
Damage only on one route Carrier handling, not the pack Specify for the harshest network

The distinction that matters most is the first two rows. They look similar on a summary report and need opposite responses.

Cost behaviour

Inserts carry a tooling cost — a cutting die for board and foam, a mould for pulp — plus a per-unit cost. Board tooling is inexpensive and pulp tooling is not, which is why moulded pulp only makes sense at volume even where it is technically the better answer.

That gives a rough hierarchy for short runs: board first, foam second, pulp only when the quantity justifies the mould.

Testing

Order a plain sample of insert and outer together, load it with the real product and drop it from about a metre onto a hard floor on several faces.

If the product shifts, tighten the cavity. If the insert deforms, step up the material. If the outer creases at a corner, load is not being distributed and the geometry needs work. Our guide to measuring products and allowing clearance covers the dimension side of the same problem.

Answers

Related questions

Should I add an insert or use a heavier outer box?

Look at what arrives damaged. Crushed boxes mean the board grade is too light for the stack. Intact boxes with damaged contents mean the product moved inside, and a heavier outer changes nothing. The second case is far more common and an insert fixes it at lower cost.

How tight should a cavity be?

1 to 2 mm clearance around the product for board, slightly less for foam because it compresses. An exact fit binds — manufacturing variance in both the product and the insert means a zero-tolerance cavity will not accept the product at all.

Can an insert let me use a cheaper outer box?

Frequently, yes. Once the contents cannot move, the outer only has to resist crushing rather than absorb internal impact. Dropping a board grade on the outer often offsets most of the insert cost, so the pair can be close to cost-neutral.

Which insert material is most recyclable?

Board and moulded pulp both go into standard paper recycling. Foam generally does not. If recyclability is firm, moulded pulp is the closest thing to foam performance that still recycles — accepting somewhat less shock absorption.

Do I need an insert for soft goods?

Rarely. A folded garment cushions itself and has no rigid parts to break. Right-sizing the outer is almost always the better answer for soft goods, and it reduces dimensional weight at the same time.

How much clearance does a foam cavity need versus board?

Slightly less for foam, because it compresses where board does not. Board wants 1 to 2 mm around the product; foam can run tighter. What neither tolerates is zero clearance — manufacturing variance on both sides means an exact cavity will not accept the product.

Why does my insert need a finger relief cut?

Because a cavity that grips well enough to protect in transit is one the customer cannot get the product out of. A relief cut is a small notch that lets a finger under the item. It costs nothing and it is the difference between a good pack and a frustrating one.

Should heavy and light items share an insert?

They can, but say so when specifying. A heavy item shifting beside a light one is a common damage mode, and the cavity for the heavy item usually needs to be tighter and deeper than its size alone would suggest.

Do I need to send the box dimensions as well as the product?

Yes. An insert is cut to the inside of the outer pack, not to the product alone, so both sets of dimensions are needed. Internal box dimensions specifically — most box specifications are quoted externally and board thickness makes the difference.

How do I test whether an insert works?

Load it with the real product and drop it about a metre onto a hard floor on several faces. If the product shifts, tighten the cavity. If the insert deforms, step up the material. If the outer creases at a corner, the load is not distributing and the geometry needs work.

Next step

Tell us what you are packing

Send the product dimensions and the quantity you need. We come back with a specification, a lead time and a written price.