Freight Class for Insulation
Insulation is very light and bulky, shipping at a high freight class — typically 150 to 300.
What is the freight class for insulation?
Batts, rolls and foam board are mostly air, so they occupy a lot of trailer space for little weight, landing in the higher classes. Compressed packaging helps, but insulation is inherently low-density.
Because freight class is density-driven, there isn’t a single fixed number for insulation — class 150–300 is the common range. Run your actual dimensions and weight below to pin it down.
The freight is the air
Insulation exists to trap air, and that same air is what makes it miserable freight. Fiberglass batts, mineral wool and rigid foam are engineered to be mostly empty space — that's how they slow heat — so they fill a trailer at almost no weight and rate at the light end of the scale, class 150 to 300. A full 53-foot trailer of loose batts can gross only a few thousand pounds. The carrier sells that space once, and the class recovers it.
The one lever that matters is compression, and it's built into the product. Fiberglass batts are packaged under heavy compression precisely so they ship at a workable class and recover their loft when the bag is opened. The difference is dramatic: the same batts loose versus factory-compressed can measure two or three classes apart. Rigid foam board can't compress, so it stays near the top of the range — its density is fixed by the board itself.
Insulation freight class: worked examples
Density is weight ÷ volume (cubic feet = L × W × H in inches ÷ 1,728). Here is how typical insulation shipments measure out:
Factory-compressed fiberglass batts — class 175
Compressed batt bags palletized, 48" × 40" × 60", 340 lb.
48 × 40 × 60 = 115,200 in³ ÷ 1,728 = 66.7 ft³. Density = 340 lb ÷ 66.7 ft³.
5.1 lb/ft³ → inside 5–6 → class 175 — even compressed, insulation is light freight.
Rigid foam board, stacked — class 200
Sheets of rigid foam board on a pallet, 96" × 48" × 36", 420 lb.
96 × 48 × 36 = 165,888 in³ ÷ 1,728 = 96.0 ft³. Density = 420 lb ÷ 96.0 ft³.
4.4 lb/ft³ → class 200 — board can't compress, so it sits high in the range.
The same batts, loose (uncompressed) — class 300
The identical 340 lb of batts allowed to loft to 90" on the same pallet.
48 × 40 × 90 = 172,800 in³ ÷ 1,728 = 100.0 ft³. Density = 340 lb ÷ 100.0 ft³ = 3.4 lb/ft³.
3.4 lb/ft³ → class 300 — losing the compression costs two classes.
Compressed, palletized, and honest about height
Ship insulation in its compressed packaging and keep it compressed — a bag that's been opened or has relaxed measures far bigger than the one you quoted. Palletize full and square; loose bags stacked with gaps sprawl and measure at their widest, and on freight this light every extra inch is pure billed air.
Rigid foam and mineral-wool board are the exception to the compression game: they're already at their fixed density, so the job is tight stacking and full-length support, not squeezing. For blown/loose-fill in bags, the same rule as kibble applies — lay bags flat and layer them to press out the air rather than standing them upright. Run the finished pallet through the calculator below; insulation quoted off catalog dimensions almost always measures worse than expected.
What affects insulation freight class
- Compressed vs. loose packaging
- Batts/rolls vs. rigid board
- Volume per pound
- Palletization
Common insulation shipments include fiberglass batts and rolls, rigid foam board, mineral wool, spray-foam kits.
Class guides covering the 150–300 range:
Calculate the freight class for your insulation
Enter dimensions and weight to get the density-based class for your exact shipment.
Density-based estimate. Some commodities carry a fixed NMFC class — check our freight class by commodity pages.
Estimated Freight Class
Density
6.51
lb/ft³
Volume
53.33
ft³
Weight
347
lb
6–7 lb/ft³ → Class 150
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Estimates only — verify freight class/NMFC and chargeable weight with your carrier.
How freight class is calculated (density scale)
Freight class is set by density = weight (lb) ÷ volume (ft³). Higher density → lower class → typically lower cost. Volume here is L × W × H × quantity.
| Density (lb/ft³) | Class |
|---|---|
| 50+ | 50 |
| 35 – 50 | 55 |
| 30 – 35 | 60 |
| 22.5 – 30 | 65 |
| 15 – 22.5 | 70 |
| 13.5 – 15 | 77.5 |
| 12 – 13.5 | 85 |
| 10.5 – 12 | 92.5 |
| 9 – 10.5 | 100 |
| 8 – 9 | 110 |
| 7 – 8 | 125 |
| 6 – 7 | 150 |
| 5 – 6 | 175 |
| 4 – 5 | 200 |
| 3 – 4 | 250 |
| 2 – 3 | 300 |
| 1 – 2 | 400 |
| 0 – 1 | 500 |
Frequently asked questions
What freight class is insulation?
Insulation typically ships at freight class 150–300. The exact class is set by density — weight divided by volume — so packaging and dimensions can move it within that range.
What affects the freight class of insulation?
The main factors are compressed vs. loose packaging, batts/rolls vs. rigid board, volume per pound, palletization. Denser, tightly packed loads rate a lower class and cost less to ship.
How do I find the exact freight class for insulation?
Measure your shipment and divide weight by volume to get density, then match it to the NMFC scale — the calculator above does this. Confirm the final class and NMFC item number with your carrier before booking.
What freight class is insulation?
Compressed fiberglass batts measure ~5 lb/ft³ → class 175; rigid foam board ~4–5 lb/ft³ → class 200; loose or lofted insulation drops to 3–4 lb/ft³ → class 250–300. It's light, bulky freight — the class sits high across the board.
Why is insulation so expensive to ship?
Because it's mostly air by design — a trailer of insulation fills its space at a tiny fraction of its weight limit, so the carrier prices the floor space it occupies, not the pounds. Keeping the product compressed is the only real cost lever.
Does compressed insulation ship at a lower class?
Yes, meaningfully. Factory-compressed batts measure several classes denser than the same product lofted or loose. Ship it in its compression packaging and keep it that way — an opened or relaxed bag measures far bigger and rebills higher.