Freight Class for Auto Parts
Auto parts have no single freight class. Density decides most of them, and parts span almost the whole NMFC scale: a pallet of 80 car batteries measures about 75 lb/ft³, class 50, while a boxed bumper cover can be close to 1 lb/ft³, class 300. Car batteries also bring federal hazmat rules, which change how you ship them more than the class does.
Car batteries in LTL: hazmat rules first
A flooded lead-acid car battery is a hazardous material: UN2794, "Batteries, wet, filled with acid, electric storage", hazard class 8, corrosive. Federal rules in 49 CFR 173.159(e) let these batteries move by highway without most hazmat paperwork, but only if the truck carries no other hazardous materials and no freight from any other shipper.
An LTL trailer carries many shippers' freight, so that exception rarely fits. A new-battery LTL shipment normally goes as regulated hazmat, with the battery entry on the bill of lading and Class 8 labels. The one exception in that rule is for consolidating batteries for recycling, which may share a truck. Batteries that pass the non-spillable tests and are marked "NON-SPILLABLE" fall under a separate section, 173.159a.
Worked examples
The battery figures come from the maker's published size and shipping weight; the bumper box is an example size. Measure your own boxes the same way.
80 car batteries on one pallet — class 50
Interstate MTP-24F batteries, 10¾ × 6⅞ × 9 7/16 in and 43.8 lb each, packed 20 per layer and 4 layers high on a 48 × 40 GMA pallet (37 lb): 42.5 inches high, 3,541 lb.
48 × 40 × 42.5 = 81,600 in³ ÷ 1,728 = 47.2 ft³. Density = 3,541 lb ÷ 47.2 ft³.
75.0 lb/ft³ → class 50, the lowest class there is. The 42.5-inch height is also well under the 60-inch limit for a 40-inch-wide pallet.
A boxed bumper cover — class 300
Say a bumper cover ships in a 72 × 30 × 20 in box weighing 30 lb.
72 × 30 × 20 = 43,200 in³ ÷ 1,728 = 25.0 ft³. Density = 30 lb ÷ 25.0 ft³.
1.2 lb/ft³ → class 300. Long plastic parts are mostly air in the box, so they rate near the top of the scale.
Building a battery pallet
Section 173.159(d) sets the pallet rules. Batteries must be firmly secured to the pallet, and the finished unit can be no taller than 1.5 times the pallet's width: 60 inches on a 40-inch-wide pallet. The unit must carry twice its own weight stacked on top without damage, or 4,000 lb if it weighs more than 2,000 lb, and the terminals must not take any of that weight.
Small lots have their own limit: one to three batteries of up to 25 lb each can go in a strong outer box, at no more than 75 lb gross. Check your carrier's own hazmat rules as well, and ask whether it adds a hazmat charge.
Mixed parts pallets
A carrier classes each pallet as one unit: total weight divided by the outside size. One long, light part on top of dense boxes sets the height and length of the whole pallet, and the dense parts pay for that space.
If a shipment has very dense and very light parts, price two pallets as well as one mixed pallet. Keep batteries off mixed pallets: the rules require them to be protected against short circuits and against damage from other freight.
Check your auto parts shipment
Enter each pallet's length, width and height from the floor, and its total weight. The calculator uses the 13-tier NMFC density scale in force since July 19, 2025.
Density-based estimate. Some commodities carry a fixed NMFC class — check our freight class by commodity pages.
Estimated Freight Class
Density
54.99
lb/ft³
Volume
53.33
ft³
Weight
2,933
lb
50+ lb/ft³ → Class 50
NMFC density scale (Docket 2025-1, effective July 19, 2025)
Free PDF includes a watermark. Pro removes it & adds your brand.
Estimates only — verify freight class/NMFC and chargeable weight with your carrier.
Uses the 13-tier NMFC density scale (Docket 2025-1). See the full freight class chart.
Frequently asked questions
What freight class are auto parts?
There is no single class. Most parts are rated by density, from class 50 for a pallet of car batteries (about 75 lb/ft³) to class 300 for a boxed bumper cover (about 1 lb/ft³). Measure and weigh each pallet.
Are car batteries hazmat for LTL freight?
Yes. Flooded lead-acid batteries are UN2794, class 8 corrosive. The highway exception in 49 CFR 173.159(e) needs a truck with no other shipper's freight, which an LTL trailer rarely is, so they normally ship as regulated hazmat.
How tall can a pallet of batteries be?
No taller than 1.5 times the pallet's width under 49 CFR 173.159(d): 60 inches on a 40-inch-wide pallet. The unit must also carry twice its own weight stacked on top, or 4,000 lb if it weighs more than 2,000 lb.
Can used batteries for recycling ship together?
Yes. The highway exception in 49 CFR 173.159(e) lets a truck carry batteries from more than one shipper when they are being consolidated for recycling, as long as its other conditions are met.
How is a mixed pallet of parts classed?
As one unit: the total weight divided by the outside length, width and height. Light, bulky parts on top set the size of the whole pallet, so price a split shipment too.