Dunnage is the loose material packed around cargo so it can’t shift, crush, or knock against other items in transit. If you’ve pulled crinkle paper out of an inbound carton or wedged air pillows into an outbound box, you’ve handled it, even if nobody called it that.
This guide covers what the word means, the main types of dunnage used in shipping, and how the cost of fill compares with the cost of a damage claim.
Key Takeaways
Definition – Dunnage is any loose material used to support, protect, separate, or secure cargo during handling, storage, and transport.
Packaging is the container – The box, mailer, crate, or pallet holds the goods. Dunnage works inside or around it, and void fill is one kind of dunnage.
Choose by job – Pick material for the job it has to do: void fill, cushioning, separation, blocking and bracing, or floor and moisture protection.
Cheap fill, expensive failures – Fill costs a little on every order. A failed pack costs much more on the orders that break, and weak packing can get a claim denied.
Write it into the SKU spec – Set the dunnage choice when you write each SKU’s packing instruction, so the packer on shift doesn’t have to guess.
What Is Dunnage?
Dunnage is any loose material used to support, protect, separate, or secure cargo while it’s handled, stored, and shipped. That includes a sheet of kraft paper in a parcel and a length of lumber bracing a crate in a container.
The U.S. trucking rules use about the same meaning.
The same federal definitions describe a dunnage bag as an inflatable bag that fills empty space between pieces of cargo, or between cargo and the vehicle wall.
That’s a broad definition. It covers almost anything whose job is to keep cargo still and undamaged, whatever it’s made of.
People often mix up three terms, so it helps to separate them:
Term | What it is | Example |
Packaging | The container or handling unit that holds and carries the goods | A corrugated carton, a polymailer, a wood crate, a pallet |
Dunnage | Any loose material inside or around the goods that supports, cushions, separates, or braces them | Foam corners, corrugated dividers, lumber blocking, inflatable bags |
Void fill | A subset of dunnage whose main job is to take up empty space so items can’t move | Crinkle paper, air pillows, packing peanuts |
The packaging is the container, and the dunnage is what keeps the product from moving inside it or against it. All void fill is dunnage, but not all dunnage is void fill. A corner protector or a wood brace has a different job than filling space.
What Is Dunnage in Shipping?
In shipping, dunnage goes around, under, or between goods so that movement, vibration, impact, and sometimes moisture don’t cause damage. It’s used anywhere cargo would otherwise slide, bounce, or rub during a trip: in a parcel, on a pallet, in a trailer, or in an ocean container.
Most of the work comes down to a few jobs. Fill keeps a product from sliding when a carton is dropped or tipped. Cushioning absorbs the shock of that drop. Separators keep two items in the same box from scuffing or cracking each other. Blocking stops a heavy load from sliding across a trailer floor. In some storage and ocean moves, boards or mats keep cargo off a floor that may be wet.
Receiving sees dunnage from the other end. Inbound freight shows up with air bags between pallets, wood bracing nailed or strapped in place, foam around equipment, and loose fill in cartons. All of it has to come off the load, and any of it can hide a crushed corner or a cracked unit until someone looks closely. It also has to be cleared before the product goes to a shelf, because loose peanuts and torn film in a pick location turn into a mispick or a contaminated order later.
Outbound dunnage has a different goal. The packer picks it so the sealed parcel or pallet survives every handoff after it leaves the building: conveyor drops, sorter transfers, truck rides, and the porch.
Dunnage in trucking
On trucks, drivers and loaders use blocks, braces, friction mats, straps, and inflatable bags so the load doesn’t shift when the truck brakes, turns, or hits a bump. Freight that moves inside a trailer can crush itself or break the doors open, which damages the cargo and puts people on the road at risk. The federal rules on this sit under 49 CFR Part 393 Subpart I, titled “Protection Against Shifting and Falling Cargo.”
Under §393.104(d), dunnage, dunnage bags, chocks, cradles, shoring bars, and blocking or bracing material can’t carry damage or defects that would weaken the securement system.
In Canada, the equivalent rules sit in National Safety Code Standard 10, the cargo securement standard that provinces and territories adopt into their own regulations. It was built alongside the US rules, so the requirements line up closely on both sides of the border.
Dunnage packaging works together with the container. It doesn’t replace a sound box, a solid pallet, or proper load restraint. A weak carton crushed under a stack will fail no matter how much paper is inside. If you’re still choosing the outer layer, this guide to choosing between boxes and poly mailers for ecommerce orders explains how format affects protection and shipping cost.
Types of Dunnage
It’s easier to choose shipping dunnage by the job it needs to do than by working through a product catalog. The jobs are void fill, cushioning, separation, blocking and bracing, and floor or moisture protection. Most materials do one or two of these well and the rest poorly.
Material | Main job | Where you see it | Weak point | What happens to it after use |
Kraft or crinkle paper | Void fill, light cushioning | Ecommerce cartons, subscription and gift boxes | Compresses under heavy or dense items, so a void can open up in transit | Usually goes in curbside paper recycling |
Air pillows | Void fill | Parcel cartons with light to medium products | Can pop or slowly deflate and leave an empty gap; weak against sharp edges | Customer punctures and discards; plastic film is often not accepted curbside |
Bubble wrap | Cushioning for surfaces | Glass, ceramics, electronics, finished wood | Bulky to store; protection drops if bubbles burst | Plastic film, usually store drop-off or trash |
Foam (sheets, planks, cut inserts) | Shock absorption and cushioning | Electronics, instruments, medical and lab equipment | Costs more and takes up storage space; harder to recycle | Often kept for reuse, otherwise trash |
Corrugated inserts or dividers | Separation and structural support | Bottles, glassware, multi-SKU kits | Has to fit the item’s shape; absorbs less shock than foam | Recycles with the cardboard box |
Packing peanuts | Void fill around irregular shapes | Odd-shaped items, reused cartons | Items can sink to the bottom; messy to clear at receiving | Starch-based pieces dissolve in water or compost; older polystyrene peanuts are often refused curbside and get reused or thrown out |
Wood or lumber blocking | Blocking, bracing, and lifting cargo off the floor | Trailers, ocean containers, crates, machinery | Splinters, fasteners, moisture; export treatment rules apply | Reused, chipped, or disposed of; international wood needs compliant marking |
Inflatable dunnage bags | Filling large gaps between pallets or against a wall | Trailers, containers, railcars | Has to be the right size and pressure; can be punctured | Deflated, then reused or discarded |
Edge or corner protectors | Spreading strap pressure and guarding corners | Pallet loads, furniture, flat-pack goods | Doesn’t stop movement by itself | Paperboard versions recycle; plastic versions are often reused |
On a pack bench, paper and air pillows are the usual parcel void fills because they’re light and quick to dispense. Bubble wrap and foam go on fragile surfaces, such as a glass panel or the face of a screen. Corrugated inserts keep two bottles or a set of components from touching. Wood blocking and dunnage bags handle heavy freight, where the goal is to stop mass from moving.
Dunnage bags are inflatable bags that fill large gaps between rows of pallets, or between cargo and a trailer or container wall. The federal definitions describe a dunnage bag as an inflatable bag intended to fill otherwise empty space between articles of cargo, or between articles of cargo and the wall of the vehicle. They’re much bigger than the small air pillows dropped into an ecommerce carton and do a different job.
Wood dunnage, also called dunnage lumber, means boards and blocks used to separate, support, or brace cargo. For international shipments, solid wood generally has to meet the ISPM 15 standard for wood packaging material. The standard singles out dunnage as a high-risk route for spreading quarantine pests.
Under the European Commission’s wood packaging guidance, regulated wood entering the EU has to be debarked, heat-treated or fumigated to ISPM 15, and stamped with the official ISPM 15 mark.
Thin wood and processed panels such as plywood are generally exempt, so check the destination country’s current rules before a container is loaded.
Custom molded or die-cut pieces make sense when the same fragile shape ships often and loose fill keeps letting it shift to one side of the box.
Dunnage Cost Versus Damage-Claim Risk
Fill is a small cost on every order or load. A failed pack is a big cost on the orders that break. Trimming the fill saves a little on thousands of shipments. A higher damage rate takes much more back on a few of them.
Parcel carriers don’t publish damage rates, so the clearest public numbers come from LTL freight (less-than-truckload, where several shippers’ pallets share one trailer). Flock Freight’s shipper research gives these figures:
How often claims happen – In the Flock Freight 2025 Shipper Research Study, shippers reported an average LTL damage rate of 1.24%. This means 1 in every 80 shipments resulted in a damage or loss claim in 2024.
What each claim costs – The same study found the average cost for these claims is around $1,796 per LTL shipment, with larger companies facing higher expenses.
What it adds up to – The largest shippers in that study reported up to $5.1M in damage and loss claims in 2024.
How much carriers cover – In Flock Freight’s earlier study of 2022 data, 86% of LTL shippers experienced damaged freight, with LTL carriers covering only 66% of those damage claims. Put those two figures together and the math is lopsided. At a 1.24% damage rate and $1,796 per claim, LTL shippers carry roughly $22 of expected claim cost on every shipment that leaves the dock, damaged or not. Fill that cuts the damage rate even slightly pays for itself quickly.
These are survey figures for LTL, not parcel, and the right amount of fill per order depends on the product. Even so, the gap between what fill costs and what one claim costs is wide in almost any operation. Replacing a broken order almost always costs more than the fill that would have protected it.
The tradeoff shows up in a handful of specific failures:
Product sliding in an oversized carton – Too much empty space, too little fill, and the item hits the box wall on every drop.
Air pillows that pop – One burst pillow leaves a void the product can move into.
Items touching in a multi-SKU box – Two hard items with nothing between them chip or scuff each other.
Crushed corners – Without edge protection or a strong enough carton, stacked weight lands on the weakest point.
Moisture on a container floor – Cartons sitting directly on a damp floor soak up water and lose strength.
A trailer load that slides forward under braking – Pallets that aren’t blocked or bagged slide forward and crush each other.
Dunnage also affects whether a claim can be filed at all. Carriers review how a shipment was packed, and weak packing gives them grounds to deny. Unishippers’ guide to shipping claims warns that carriers often deny claims due to “insufficient packaging” — even if mishandling occurred. A good pack doesn’t guarantee a payout. A poor one makes a denial much more likely, so keep packing photos, records of the materials used, and the original box until any claim is resolved.
Right-sizing ties the cost side together. When the carton or mailer is chosen to fit the product’s largest dimension, there’s less empty space to fill and less chance of paying dimensional-weight charges for air. Dimensional weight is the billing method carriers use for bulky, light parcels, based on box size rather than actual weight. Right-sizing is a decision made at the pack station, before anyone grabs fill.
How a Warehouse Chooses Dunnage
The dunnage choice belongs in the SKU packing instruction. If it’s left to whoever happens to be packing that hour, the same product ships with paper on Monday, air pillows on Tuesday, and no fill on Wednesday. Damage patterns that vary like that are hard to trace.
A practical decision sequence for each SKU looks like this:
Check fragility and surface – Decide whether the item can break and whether its finish scuffs, since a hard drop and a light rub call for different materials.
Measure the remaining void – Choose the right carton or mailer first, then see how much empty space is left to fill.
Check for contact – If several items share a box, decide whether they can touch or need inserts or dividers between them.
Separate bracing from cushioning – Heavy or palletized freight usually needs blocking, bags, or straps to stop movement, more than it needs soft padding.
Weigh the cost of bulk – Note whether the material adds weight or size that pushes up storage space or shipping charges.
Plan for disposal – Consider how the customer will get rid of it. Paper and corrugated are usually easier to put in curbside recycling than plastic film.
Receiving belongs in the same process. Whoever unloads inbound freight has to remove bracing and straps safely, check for damage the dunnage may be hiding, and clear loose material before the product is stocked. A clean receive gives you an accurate count, damage logged at the dock, and bins free of packing debris. You can only trust the outbound pack spec if the inbound product was what you thought it was. For background on how inventory moves from the dock to the shelf to the pack station, see this overview of how a 3PL receives, stores, picks, and packs orders.
In a fulfillment operation like GoBolt’s fulfillment centers, brands can set SKU-level packing instructions. Standard cartons and polymailers are chosen from the product’s largest dimension, so the building doesn’t have to stock every possible box size. Brands with custom packaging can send it to the fulfillment center to use in place of standard stock. Whoever does the packing, the logic doesn’t change: fit the container first, then pick dunnage for the specific gap that’s left.
At the pack bench, our teams keep kraft paper on hand for everyday parcel orders. If a brand’s damage or return photos point to the same failure more than once, our Operations team updates that SKU’s packing instruction so the next shift packs it the new way.
Match the Damage to the Job the Material Missed
If the product moved inside the carton, or the load moved in the trailer, the dunnage didn’t do the job that gap required. Damage usually tells you which job failed: a scuff points to separation, a cracked corner to cushioning, and a product that slid to one end to void fill or bracing.
As a next step, pull a few recent damage or return photos. Label each one as a void, cushion, separation, bracing, or moisture failure. Then change the packing spec for that SKU before you buy any new materials, because the fix is often a smaller box or one divider.
FAQs
What does dunnage mean?
Dunnage is any loose material used to support, protect, separate, or secure cargo during handling, storage, and transport. Kraft paper in a parcel and lumber bracing a crate in a container are both dunnage.
Is dunnage the same as packaging?
No. Packaging is the container that holds the goods, such as a carton, polymailer, crate, or pallet. Dunnage is the loose material inside or around that container that keeps the goods from moving or breaking.
What's the difference between dunnage and void fill?
Void fill is one type of dunnage. Its job is to take up empty space so an item can't slide around. Dunnage also covers cushioning, dividers, blocking and bracing, and floor protection.
Is dunnage recyclable?
It depends on the material. Kraft paper and corrugated inserts usually go in curbside recycling. Plastic film, such as air pillows and bubble wrap, is often refused curbside, and wood dunnage is usually reused, chipped, or thrown out.
