How do you calculate freight class for multiple pallets?

Add up the total weight of every pallet and the total volume of every pallet, then divide total weight by total volume to get the shipment's aggregate density in pounds per cubic foot. Look that single density up on the NMFTA scale to get one class for the whole line. You do not class each pallet separately or average the classes.

Can you average the freight class of different pallets?

No. Averaging classes gives the wrong number because class isn't linear with density. A shipment with a Class 70 pallet and a Class 250 pallet does not average to Class 160 — it's rated by the combined weight and volume, which might land it at Class 100. Only aggregate density gives the class the carrier will bill.

What is aggregate density?

Aggregate density is the density of a whole shipment treated as one unit: the total weight of all handling units divided by their total volume in cubic feet. It's how LTL carriers rate a line that has several different pallets, and it can differ from the density of any single pallet on it.

Do I use total weight and total volume of all pallets?

Yes. Sum the weight of every pallet (including the pallets themselves) and sum the volume of every pallet, then divide total weight by total volume. That single density sets one class for the entire shipment.

Freight Class for a Multi-Pallet Shipment

When several different pallets ship on one BOL line, carriers don’t class them pallet-by-pallet and they don’t average the classes. They rate the whole line by its aggregate density — total weight of every pallet divided by total volume, calculated once. Class each pallet on its own and you’ll hand the carrier a number that doesn’t match the bill.

A worked example

Two pallets on one shipment — one heavy, one light and bulky:

Handling unit	Size & weight	Density	On its own
Pallet A	48×40×48 in, 800 lb	15.0 PCF	Class 70
Pallet B	48×40×60 in, 200 lb	3.0 PCF	Class 250
Whole shipment	1,000 lb ÷ 120 ft³	8.33 PCF	Class 100

The shipment is Class 100 — not 70, not 250, and not the “average” of 160. Only the combined density gives the class the carrier bills.

Why per-pallet classing gets it wrong

Freight class isn’t linear with density, so you can’t mix classes by averaging them — the math simply doesn’t work that way. And a carrier rating a single BOL line doesn’t care how you divided it into pallets; it cares how much the whole line weighs and how much trailer space it occupies. Put those two totals together and you get one density, and one class. Split the shipment up first and every number you calculate is answering a question the carrier isn’t asking.

The aggregate-density method, step by step

1. Measure each pallet to its farthest points, pallet included, and get its volume (L × W × H in inches, ÷ 1,728 for cubic feet). 2. Add up every pallet’s volume for the shipment’s total cubic feet. 3. Add up every pallet’s weight — including the weight of the pallets themselves — for the total pounds. 4. Divide total pounds by total cubic feet for the aggregate density, and read that PCF off the class chart. That single class covers the line.

One shipment, one density, one class. The pallets are just how it’s stacked — not how it’s rated.

Where it bites — and why the tool exists

This is the single most common reason a “correct” class still gets reclassed: the shipper classed the heaviest pallet, or averaged, and the carrier rated the aggregate. Doing it by hand across a mixed load — different footprints, different heights, pallet tare weights — is where errors creep in. The Multi-Pallet Freight Class tool takes every unit, returns the aggregate class and the per-unit breakdown, and matches the method carriers use — the one thing single-input calculators can’t do. For the fundamentals first, start with the Freight Class & NMFC guide.