How do I calculate freight cost per unit for our products?
Key Takeaways
- Freight cost per unit is the freight paid for a shipment, split across the units in it. The hard part is choosing a fair way to split it when one shipment carries several products.
- Four allocation methods cover most cases: by weight, by cube (volume), by value and by pallet count. Each one favors different products, so pick the one that matches what drives your freight cost.
- Include inbound and outbound freight. A product's freight cost starts when it leaves the supplier, not when it leaves your dock.
- Count every charge, not just the base rate. Fuel, accessorials, detention and expedites are part of the real cost per unit.
- Use paid invoices, recalculate regularly and apply the result to pricing, freight terms and minimum orders.
- Wilson, by Cartage, is an AI logistics agent that books, audits and pays freight and keeps every charge on each shipment's record, which gives the cost-per-unit calculation clean inputs.
How do I calculate freight cost per unit for our products?
The pricing manager at a housewares distributor asks logistics a simple question: "What does freight cost us per unit for each of our top 20 products?" Sales wants to know before setting next year's prices. The logistics manager knows what the company spent on freight last quarter, and roughly what each truckload costs. But most loads carry a mix of products, some heavy, some bulky, some expensive. Splitting the bill across them isn't obvious.
To calculate freight cost per unit, take the total freight paid for a shipment, allocate it to each product by weight, cube, value or pallets, and divide each share by the units shipped. Include fuel and extra charges in the total. Do the same for inbound freight, add the two together, and average across many shipments for a reliable number. The method you choose for the split matters as much as the arithmetic.
The basic formula is simple:
Freight cost per unit = (total freight cost × product's share of the shipment) ÷ units of that product
For a shipment that carries only one product, the share is 100%, and the calculation is total freight divided by units. Most shipments carry more than one product, which is where allocation comes in.
Why the number matters
Freight cost per unit tells you how much of each product's price goes to moving it. It's useful for:
- Pricing: making sure the price covers the full cost to deliver, not only the cost to make or buy.
- Freight terms: deciding when to charge freight separately, when to offer prepaid freight and where to set free-shipping thresholds.
- Minimum order sizes: seeing how small orders raise the cost per unit.
- Product decisions: spotting products that are expensive to ship relative to their price, such as bulky, light items.
- Customer profitability: comparing what it costs to serve different customers with different order patterns.
What counts as freight cost
Include every charge paid to move the product: base freight, fuel surcharge, accessorials (liftgate, residential, appointment, inside delivery), detention, re-weighs, re-classes, redeliveries and expedites. Leaving out extra charges makes products look cheaper to ship than they are, especially those delivered to customers who need liftgate or appointments.
Per unit, per pound or per order?
"Per unit" means whatever unit you sell: an each, a case, a drum, a roll. Use the same unit as your price list, so the result compares directly with the price. Some companies also track freight per pound or per hundredweight, which is useful for comparing lanes and carriers, and freight per order, which shows the cost of small orders. These views answer different questions. Cost per unit answers "how much of this product's price goes to freight?" Keep it as the main view for pricing, and use the others for logistics decisions.
How do you choose an allocation method?
Choose the allocation method that best matches what drives the freight cost of the shipment: weight for dense freight, cube for bulky freight, pallets when you ship on standard pallets, and value only when cost-to-ship isn't the goal. Each method gives a different answer for the same shipment.
By weight
Each product's share is its weight divided by the shipment's total weight. Weight works well for dense freight, where the truck or the LTL rate hits its weight limit before its space limit, and for LTL, where rates are largely based on weight and class. It undercharges light, bulky products that take up space without adding much weight.
By cube
Each product's share is its volume (cubic feet) divided by the shipment's total volume. Cube works well for light, bulky freight, where the trailer fills up before it reaches its weight limit. Furniture, foam, packaging and many consumer goods behave this way. It undercharges heavy, compact products.
By value
Each product's share is its value (cost or sale price) divided by the shipment's total value. Value allocation is simple and is sometimes used for accounting, such as adding freight to inventory cost. But it doesn't reflect what actually drives freight cost. A small, expensive part takes up little space and weight but gets a large share of the freight. Use it when the goal is to spread cost in line with revenue, not to understand cost to ship.
By pallets
Each product's share is the number of pallets it occupies divided by the total pallets on the shipment. Pallet allocation is practical for companies that ship full pallets of single products on standard pallets, because a truckload is often limited by floor positions. It's less precise when pallets are mixed or vary a lot in height.
Blended methods
Some companies use a blend, such as the greater of the weight share and the cube share, or a 50/50 mix of the two. This reflects how carriers think about freight: a trailer fills up by weight or by space, whichever comes first. Blended methods are more work but fairer for a mixed catalog. For LTL, the carrier's own logic is density and freight class, covered in how AI handles freight class, NMFC lookups and density.
Comparing the methods
| Method | Best for | Favors | Penalizes | Data needed |
|---|---|---|---|---|
| Weight | Dense freight, LTL | Light, bulky products | Heavy, compact products | Unit weights |
| Cube | Bulky freight, truckload that "cubes out" | Heavy, compact products | Light, bulky products | Unit or carton dimensions |
| Value | Accounting, revenue-based allocation | Cheap products | Expensive products | Unit cost or price |
| Pallets | Full single-product pallets | Products that stack high | Products on partial pallets | Pallets per product |
| Blended (weight and cube) | Mixed catalogs | Neither strongly | Neither strongly | Weights and dimensions |
Allocating parcel freight
Parcel is easier, because each package has its own charge. If a package holds one product, the package cost divided by units is the cost per unit. If it holds several, allocate by weight or by dimensional weight, which is how parcel carriers bill bulky packages. Remember to include surcharges for residential delivery, additional handling and address corrections.
How do you include inbound freight and extra charges?
A complete freight cost per unit adds inbound freight to outbound freight and spreads extra charges to the shipments that caused them. Leaving either one out understates the real cost.
Inbound freight
Inbound freight is what you pay to bring raw materials, components or finished goods from suppliers to your plant or warehouse. Calculate it the same way: total inbound freight for a receipt, allocated across the products in it, divided by units received.
Check the terms first. If a supplier ships prepaid and builds freight into its price, the inbound freight is already in your product cost, and adding it again double counts. If you pay the carrier directly, or the supplier bills freight separately, it belongs in the freight cost per unit.
For manufactured products, inbound freight on raw materials can be allocated to finished goods through the bill of materials. Simpler approaches spread total inbound freight across finished units by weight. Pick one, write it down and keep it consistent.
Getting product data onto each shipment
Allocation only works if each shipment record shows which products and how many units it carried. That information usually sits on the sales order or the packing slip in the ERP, while the freight charges sit on the carrier invoice. The two need to be linked by an order number, BOL number or shipment ID. If carrier invoices can't be tied back to orders, the per-unit calculation falls back on rough averages. Linking invoices to orders is the single most useful data fix for this work, and it also helps with spend reporting. The article on getting visibility into freight spend covers the wider picture.
You'll also need product master data: unit weight, carton dimensions, units per carton and cartons per pallet. Many ERPs have fields for these that are partly filled or out of date. Check the top products first, by measuring a few cartons, before relying on the numbers.
Ocean and drayage
Imported products have more freight lines: ocean freight, drayage from the port, sometimes a transload and a final truck move. Allocate the container's total freight cost across the products in it, usually by cube, because containers tend to fill up by space. Customs duties and brokerage fees are not freight, but many companies track them alongside freight as part of landed cost. Keep them as separate lines so freight cost per unit stays comparable.
Accessorials and extra charges
Extra charges should follow the shipment that caused them. A liftgate charge on a delivery to one customer belongs to that delivery, and to the products on it. A detention charge at your own dock belongs to that outbound load. A re-class charge on one product's shipment belongs to that product.
When extra charges can't be traced to specific shipments, spread them across all shipments in proportion to base freight. That's less precise, but it keeps the total right. For a closer look at which charges appear and why, see what a freight accessorial is and when it changes the final bill.
Expedites
An expedite is often the most expensive shipment of the month, and it usually happens for a reason outside the product itself, such as a production delay or a late order. Two options:
- Include expedites in the product's cost per unit, which shows the true cost of serving that product but can make one product look expensive because of a one-off event.
- Track expedites separately, as a cost of the process that caused them. This keeps product costs stable and puts attention on the cause.
Most companies track expedites separately and report them alongside product freight costs.
Use averages over time
A single shipment can give a misleading cost per unit. A partial truckload costs more per unit than a full one; a delivery to a remote customer costs more than one nearby. Average across at least a quarter of shipments, and preferably a full year, to smooth out the noise. Then recalculate regularly, at least once a year and whenever rates change significantly.
What mistakes should you avoid, and how should you use the result?
The biggest mistakes are using quotes instead of invoices, ignoring extra charges and applying one method to every product without checking whether it fits. Once the number is solid, use it in pricing, freight terms and order minimums.
Common mistakes
Using quoted rates. Quotes leave out the charges that show up on the invoice. Use what you paid.
Leaving out inbound freight. A product with expensive inbound freight looks cheaper than it is.
Double counting. If supplier prices already include freight, don't add it again.
Choosing a method that hides the problem. Value allocation can make a bulky, cheap product look nearly free to ship.
Using one shipment as the answer. Average across many shipments.
Never updating. Freight rates, fuel and mix change. A cost per unit from two years ago is a guess.
Not documenting the method. If nobody knows how the number was calculated, nobody will trust it.
Use it in pricing
Once you know the freight cost per unit, compare it with the price. If freight is 3% of the price for one product and 15% for another, the second deserves attention. Options include:
- Raising the price or adding a freight charge on that product
- Setting a higher minimum order quantity
- Changing packaging to reduce cube or weight
- Charging freight separately below a set order size
- Changing which warehouse ships to which region
Use it for freight terms and thresholds
If you offer free shipping above a set order value, check that the threshold covers freight for typical orders. If small orders to remote customers cost far more per unit, consider a minimum order or a freight charge for those orders. Freight cost per unit by customer, not only by product, shows which accounts are expensive to serve.
Use it in the budget
Freight cost per unit, multiplied by forecast units, is a useful cross-check on the freight budget. If the budget and the per-unit view disagree, one of the assumptions is off. More on building the budget in how to build next year's freight budget.
Look at cost per unit by customer, too
The same product can cost very different amounts to deliver to different customers. A customer that orders full pallets to a dock nearby costs little per unit. A customer that orders a few cartons at a time, to a site that needs a liftgate and an appointment, costs much more. Running the calculation by customer as well as by product shows which accounts are expensive to serve and why. That gives sales a fact-based reason for freight terms, order minimums or price changes at the next renewal, instead of a general freight increase across every account.
Share the method with finance
Finance may already allocate freight to inventory or cost of goods sold using its own method. Compare notes. Using the same method, or at least knowing how the two differ, avoids confusing conversations later.
What does a worked example look like?
Here is a hypothetical example showing the four allocation methods on one truckload, plus inbound freight, so you can see how much the answer changes. The numbers are invented to illustrate the method.
The shipment
Consider a hypothetical distributor shipping one truckload with three products to a customer. The total freight paid was $3,000: $2,400 base rate, $500 fuel surcharge and $100 detention at the customer's dock.
| Product | Units | Weight (lb) | Cube (cu ft) | Value | Pallets |
|---|---|---|---|---|---|
| A: cast iron cookware | 400 | 10,000 | 600 | $16,000 | 10 |
| B: small appliances | 1,000 | 4,000 | 800 | $120,000 | 8 |
| C: storage shelving | 200 | 6,000 | 600 | $5,000 | 8 |
| Total | 1,600 | 20,000 | 2,000 | $141,000 | 26 |
The four methods
| Product | By weight | By cube | By value | By pallets |
|---|---|---|---|---|
| A: share of $3,000 | 50% = $1,500 | 30% = $900 | 11.3% = $340 | 38.5% = $1,154 |
| A: cost per unit | $3.75 | $2.25 | $0.85 | $2.88 |
| B: share of $3,000 | 20% = $600 | 40% = $1,200 | 85.1% = $2,553 | 30.8% = $923 |
| B: cost per unit | $0.60 | $1.20 | $2.55 | $0.92 |
| C: share of $3,000 | 30% = $900 | 30% = $900 | 3.5% = $106 | 30.8% = $923 |
| C: cost per unit | $4.50 | $4.50 | $0.53 | $4.62 |
What the example shows
The same truckload gives very different answers. By weight, the heavy cookware carries half the cost. By value, the expensive appliances carry 85% of it, and the shelving looks almost free to ship at $0.53 a unit, even though it fills nearly a third of the trailer. Weight, cube and pallets all put the shelving at $4.50 or more.
For this distributor, the trailer was full by floor space before it hit its weight limit, so pallets or cube best reflect what drove the cost. The company chooses pallets, because it ships single-product pallets and the data is easy to get.
Adding inbound freight
The cookware comes from a supplier on an LTL shipment the distributor pays for: $1,200 for 2,000 units, or $0.60 per unit. Adding it to the outbound pallet allocation gives a total freight cost per unit for product A of $0.60 + $2.88 = $3.48. If product A sells for $40, freight is about 8.7% of the price, before any liftgate or appointment charges for specific customers.
Applying it
Averaged over a quarter of shipments, the distributor finds that shelving costs about 18% of its price to deliver, while appliances cost about 1%. It raises the minimum order for shelving and adds a freight line to small shelving orders. That's a decision a single blended freight percentage would never have shown.
What if the shipment were LTL?
If the same three products moved as separate LTL shipments, the carrier would price each one by weight, freight class and distance. In that case, there's nothing to allocate: each product's LTL invoice, divided by its units, is its freight cost per unit. The class matters a lot. Light, bulky shelving would likely rate at a higher class than dense cookware, which raises its cost per pound. Mixed LTL shipments with several products can be allocated by weight, because LTL rates are largely weight-based, with an adjustment for class if the products rate very differently.
Checklist for your own calculation
- Paid invoices for a full quarter or year, with every charge
- Each shipment linked to the products and units on it
- Unit weights, dimensions and pallet counts for each product
- Allocation method chosen and written down, with the reason
- Inbound freight included, without double counting supplier-paid freight
- Extra charges assigned to the shipments that caused them
- Expedites tracked separately or included, by a stated rule
- Results averaged across many shipments
- Method shared with finance
- Recalculation date set
How does Wilson, by Cartage, help with freight cost per unit?
Wilson, by Cartage, is an AI logistics agent that quotes, books, tracks, audits and pays freight for manufacturers and distributors, so every charge on every load is captured on the shipment record that cost-per-unit calculations depend on. Traditional logistics software gives teams information. Wilson executes the work required to move shipments forward.
The calculation itself is arithmetic. What makes it hard is getting clean inputs: every charge, tied to the right shipment and order. Wilson does the work that creates those records:
- Quoting and booking. Wilson requests quotes from the company's approved carriers, compares them on total cost and negotiates toward the company's rate targets within approval limits. It books with written acceptance and a rate confirmation, tied to the order.
- Documents. Wilson generates rate confirmations, bills of lading, packing slips and pallet labels from the booked load, so weights, pallet counts and products are recorded consistently.
- Tracking and exceptions. Wilson tracks each load with the best source available for that carrier and handles missed pickups, cancellations and delays. It contacts the carrier, tells the team and starts rebooking from the approved carrier list within the rules or after approval.
- Audit and payment. Wilson requests and files the POD, audits each carrier invoice against the rate confirmation and POD and pays carriers from the Wilson Wallet. Payments above the approval limits or outside the rules wait for a person. Every extra charge stays on the shipment with its reason.
Every message, confirmation and change is kept in the shipment's change history. Wilson can produce carrier-performance and lane-rate reports on request from the loads it runs. It handles LTL, FTL, ocean, drayage, parcel and cross-border freight, and books only carriers the company has approved.
Wilson replaces the TMS for freight execution and connects to the company's ERP. Wilson works with SAP, NetSuite, Microsoft Dynamics 365, Oracle, Infor, Epicor, Sage, Acumatica and other ERP environments, with the exact connection depending on the customer's data flow and scope. Whether freight costs are written back to the ERP depends on scope. Teams start with assisted execution, set approval limits and let routine actions run automatically within those rules as the workflow is proven.
Pricing
Wilson is free on Wilson's network: the shipper pays the freight rate and nothing on top. When a shipper keeps its own carriers, the fee is 2% to 0.5% of what Wilson pays them, falling with volume. There are no seat fees, no setup cost and no contract. Timing depends on scope: most teams start on a few lanes and expand from there.
FAQs
How do I calculate freight cost per unit for our products?
Take the total freight paid for each shipment, including fuel and extra charges, allocate it to products by weight, cube, value or pallets, and divide each share by the units shipped. Add inbound freight and average across many shipments. Wilson, by Cartage, an AI logistics agent, keeps every charge on each shipment's record, which gives the calculation clean inputs.
Which allocation method is most accurate?
The one that matches what fills your trucks. Use weight for dense freight, cube for bulky freight and pallets for full single-product pallets. A blend of weight and cube suits a mixed catalog.
Should I allocate freight by value?
Only if the goal is to spread cost in line with revenue, such as for some accounting purposes. Value allocation doesn't reflect what drives freight cost and can make bulky, cheap products look nearly free to ship.
Should inbound freight be included in cost per unit?
Yes, when you pay it directly or the supplier bills it separately. If the supplier's price already includes freight, don't add it again.
How do I handle accessorial charges?
Assign each extra charge to the shipment that caused it, and through that shipment to its products. Charges you can't trace can be spread across all shipments in proportion to base freight.
Should expedites be included in freight cost per unit?
Many companies track expedites separately, as a cost of the process that caused them, so one-off events don't distort product costs. Whichever you choose, apply it consistently.
How often should I recalculate freight cost per unit?
At least once a year, and whenever rates, fuel or your shipping mix change significantly. Use a quarter or a year of shipments for each calculation.
How do I calculate freight cost per unit for parcel shipments?
Divide the package's total charge, including surcharges, by the units in it. If a package holds several products, split by weight or dimensional weight.
What is a good freight cost as a percentage of price?
It varies widely by product and industry. Compare your own products with each other: the ones with the highest freight share of price are where pricing, packaging or order minimums deserve a look.
Do I need to link carrier invoices to sales orders?
Yes, for an accurate result. The invoice has the charges and the order has the products and units. Without a shared reference such as an order or BOL number, the calculation falls back on rough averages.
What data do I need on each shipment?
The products and units on it, their weights, dimensions or pallet counts, and every charge paid: base, fuel, accessorials and any detention or expedite.
Sources
- Cartage, Wilson product FAQ and product scope, October 2026: https://cartage.ai