Freight Class Calculator for Auto Parts
Auto parts are the widest density spread in freight. A crated engine block rates class 50 territory at 45 pounds per cubic foot; a pallet of bumpers and body panels rates class 100 or higher at a fraction of that. Distribution warehouses and parts suppliers therefore ship both extremes in one order — and the rule that catches them is simple: when different commodities share a handling unit, the highest class of anything on the pallet applies to the whole pallet.
Run a mixed pallet through the calculator — a 48×40×36-inch pallet at 320 pounds computes to 8.0 pounds per cubic foot, class 100 today (the legacy chart would have said 110) — then read how the pros segment loads so the dense parts stop subsidizing the bulky ones.
Scale weight of the whole handling unit — goods plus pallet, crating and banding.
Include the pallet — typically 5–6 in.
For multi-pallet shipments, calculate each pallet separately and quote the class of the densest one unless the carrier lets you list them as separate handling units.
Freight class
Class 100
Density basis — 8 lb per cubic foot under the NMFC scale effective July 19, 2025.
- Density
- 8 lb/ft³
- Cube
- 40 ft³
- Legacy chart would say
- Class 110
Measured at the extreme points of the finished handling unit — pallet, packaging and overhang included.
Quote the 2025 figure — the old chart (with classes 110, 150, 200, 500) no longer governs density classification, and quoting it invites a reclass fee.
Density decides the class for most freight since July 2025, but stowability, handling and liability can still override it, and the commodity's NMFC item number governs. Confirm the item number with your carrier before quoting.
| Density (lb/ft³) | Class | Legacy chart (pre-2025) |
|---|---|---|
| 0 – 1 | Class 400 | 1 – 2 |
| 1 – 2 | Class 300 | 2 – 3 |
| 2 – 4 | Class 250 | 3 – 4 |
| 4 – 6 | Class 175 | 5 – 6 |
| 6 – 8 | Class 125 | 7 – 8 |
| 8 – 10 | Class 100 | 9 – 10.5 |
| 10 – 12 | Class 92.5 | 10.5 – 12 |
| 12 – 15 | Class 85 | 12 – 13.5 |
| 15 – 22.5 | Class 70 | 15 – 22.5 |
| 22.5 – 30 | Class 65 | 22.5 – 30 |
| 30 – 35 | Class 60 | 30 – 35 |
| 35 – 50 | Class 55 | 35 – 50 |
| 50+ | Class 50 | 50+ |
Starting values are set for a typical auto parts scenario — change any field to match yours. Need the plain version? Freight Class Calculator.
One order, many classes
Illustrative ranges across the parts catalogue — the spread is what makes mixed-pallet discipline worth money:
| Part family | Typical density | Typical class today |
|---|---|---|
| Crated engines, blocks, differentials | 40+ lb/ft³ | Class 60–50 |
| Brake rotors, calipers, boxed steel parts | 25–35 lb/ft³ | Class 65–60 |
| Body panels, hoods, fenders | 8–15 lb/ft³ | Class 100–70 |
| Bumpers, trim, lighting, bulky plastics | 2–8 lb/ft³ | Class 250–100 |
The highest-class rule, and how to defeat it
When bumpers and brake rotors share a pallet, the pallet classifies at the bumpers' class — the highest present — unless the bill of lading lists them as separate handling units. That single rule is why two warehouses shipping identical orders can pay materially different freight. The playbook:
- Segment by density into separate handling units: rotors on one pallet, bumpers on another. Each unit then rates its own class instead of the mix rating at the worst one.
- Build BOLs with real item descriptions and NMFC item numbers per handling unit — "auto parts, 1 pallet" is an invitation for the carrier's version of the classification.
- Load heavy, dense parts at the bottom of any shared pallet and brace them; the classification rule does not change, but the damage rate does.
- Never hide bulky parts under dense ones to game the measurement — carriers inspect, and inspection finds the bumpers.
Reclass risk specific to parts freight
- Carriers weigh and measure each pallet at its extremes; a mixed pallet's density is computed from the whole unit, so one protruding bumper shifts every number.
- Under the July 2025 scale, an 8.0 pcf pallet rates class 100 where the legacy chart said 110 — quoting either old memory or old charts produces systematic mismatches.
- Hazardous parts — airbag inflators, pressurized components, batteries — carry hazmat handling obligations that override density entirely and require trained-handling carriers.
- Core returns travel the same rules as new parts; used, oily cores can add handling considerations on top of the density class.
- Keep scale tickets and pallet measurements for every SKU family: when the carrier's inspection result differs from the BOL, documentation is the difference between a reversed adjustment and a paid one.
Frequently asked questions
- What freight class are auto parts?
- Anywhere from class 50 to 250 depending on the part. Dense machined components and crated engines rate at the low end; body panels, bumpers and bulky trim rate at the high end. Class comes from the handling unit's density plus the NMFC item number, so the same order can legitimately contain several classes.
- What class is a pallet of mixed auto parts?
- The highest class of anything on the pallet, unless the bill of lading lists the commodities as separate handling units. Mixing brake rotors with bumpers makes the whole pallet rate as bumpers. Separating them onto their own pallets lets each ship at its own class — usually a net saving even with an extra handling unit.
- How many pounds per cubic foot is a typical parts pallet?
- It varies enormously by product mix. Our worked example — 320 pounds across a 48×40×36-inch pallet — computes to 8.0 pcf, class 100 under the July 2025 scale. A pallet of rotors can exceed 25 pcf; a pallet of grilles can fall under 5. Compute each pallet, never the average.
- Does the 2025 NMFC change affect auto parts?
- Yes. Docket 2025-1 migrated many commodity listings to density-based classification and rebuilt the density scale into 13 bands. Several mid-density parts families moved class — one reason quoting from a pre-2025 chart or from memory produces reclass fees. Verify current item numbers with your carrier.
- Do core returns classify the same as new parts?
- The density rules are identical — class comes from the handling unit. What differs in practice is condition: used, oily or leaking cores can trigger handling adjustments, and some carriers ask that cores be drained and bagged. Pack cores to the same measurement discipline as new parts and the class math works the same.
- How do airbags and other regulated parts change the shipment?
- Hazardous materials — airbag inflators and modules among them — carry hazmat classification and handling obligations that override density-based classes entirely. They require trained certification, specific carriers and hazmat fees. Never fold a regulated part silently into a general-parts pallet.