- Measure shipment dimensions in inches, including the pallet. Use the longest measurement on each axis.
- Enter total weight in pounds, including pallet and packaging.
- The calculator computes density (lb/ft³) and looks up the corresponding NMFC class on the standard density table.
- Verify the class against your commodity. Density determines class for most non-hazardous, non-fragile freight, but some commodities have fixed NMFC class assignments regardless of density (electronics, hazmat, automotive parts, etc.).
- Use the class for LTL freight quotes. Lower class numbers = cheaper shipping. Misclassifying freight is the #1 cause of reclassification fees from carriers.
Freight Class Calculator
Determine NMFC freight class from shipment density. Calculate density (lb/ft³) from dimensions and weight, then look up the corresponding LTL class.
Enter shipment dimensions (including pallet) and total weight.
Pallet tip: include the pallet in your dimensions and weight. A typical wood pallet adds 30-40 lbs and 4-6 inches of height to your shipment.
NMFC Freight Class
100
Average (boxed/crated goods)
| Volume | 53.33 ft³ |
| Density | 9.38 lb/ft³ |
| Pallet positions (approx) | 2 |
NMFC Density-to-Class Table
| Density (lb/ft³) | Class | Typical Examples |
|---|---|---|
| 0+ to 0.99 | 500 | Lowest density (gold dust, ping pong balls) |
| 1+ to 1.99 | 400 | Extremely light (deer antlers, light fixtures) |
| 2+ to 2.99 | 300 | Very light (wood cabinets, tables) |
| 3+ to 3.99 | 250 | Very light (mattresses, plasma TVs) |
| 4+ to 4.99 | 200 | Light (sheet metal parts) |
| 5+ to 5.99 | 175 | Light (clothing, couches stuffed) |
| 6+ to 6.99 | 150 | Below average (auto sheet metal) |
| 7+ to 7.99 | 125 | Below average (small appliances) |
| 8+ to 8.99 | 110 | Slightly below average (cabinets, framed art) |
| 9+ to 10.49 | 100 | Average (boxed/crated goods) |
| 10.5+ to 11.99 | 92.5 | Average |
| 12+ to 13.49 | 85 | Above average (crated machinery) |
| 13.5+ to 14.99 | 77.5 | Above average |
| 15+ to 22.49 | 70 | Above average density (food, auto parts) |
| 22.5+ to 29.99 | 65 | High density (tile, books) |
| 30+ to 34.99 | 60 | High density |
| 35+ to 49.99 | 55 | Very dense |
| 50+ | 50 | Very dense (heavy machinery, steel) |
How to Use the Freight Class Calculator
How NMFC Freight Class Is Determined
The National Motor Freight Classification (NMFC) uses density as the primary factor for assigning freight class to most LTL (Less-than-Truckload) shipments. The system has 18 classes from 50 (densest, cheapest) to 500 (lightest, most expensive).
Density (lb/ft³) = Weight (lb) / Volume (ft³) Volume (ft³) = (L × W × H in inches) / 1,728 Class = lookup(Density, NMFC density table)
Example: A 48" × 40" × 48" pallet weighing 500 lbs.
- Volume = (48 × 40 × 48) / 1,728 = 53.33 ft³
- Density = 500 / 53.33 = 9.38 lb/ft³
- Class 100 range is 9-10.5 lb/ft³ → Class 100
Beyond density, NMFC also considers four other factors for special commodities: stowability (regular vs irregular shapes), handling (special equipment needed), liability (theft/damage risk), and commodity type (some items have fixed class assignments).
Misclassifying freight is the most common cause of reclassification fees, which can add $50-300+ per shipment. Carriers re-weigh and re-measure shipments at hubs and bill the difference if class is wrong. Always measure accurately and round dimensions up to the nearest inch.
Lowering Your Freight Class: Density Strategies That Cut Shipping Costs
Freight class is the single biggest factor in LTL shipping cost. Moving from Class 250 to Class 125 typically cuts the rate by 40-50%. Three legitimate strategies to reduce class:
| Strategy | Effect | When It Works |
|---|---|---|
| Tighter packaging | Reduces dimensional volume → raises density → lowers class | Bulky packaging with lots of foam, large boxes for small items |
| Disassemble large items | Pack in smaller, denser configurations | Furniture, exercise equipment, modular displays |
| Consolidate small shipments | One denser pallet vs multiple light boxes | Multiple SKUs going to same destination |
| Add filler weight (rarely worth it) | Increases density but adds shipping weight | Only when class drop saves more than weight cost |
Three rules that veteran logistics managers know:
- Always round up dimensions to the nearest inch. A 47.5" pallet measures as 48". Underreporting dimensions is the #1 trigger for reclassification fees, and the difference often costs more than the savings.
- Pallet positions matter as much as class. A 4-pallet shipment is usually billed by space, not weight. Stacking and consolidating can be more impactful than chasing class.
- Some commodities have fixed NMFC class. Electronics, hazmat, automotive parts, and many household goods are classed by commodity number, not density. Check the NMFC item number before relying on density.
Frequently Asked Questions
Freight class is a standardized rating set by the National Motor Freight Classification (NMFC) used to determine LTL (Less-than-Truckload) shipping cost. Classes range from 50 (densest, cheapest) to 500 (lightest, most expensive). Class is primarily based on density (lb/ft³), with adjustments for handling difficulty, stowability, and liability. Lower class = lower freight cost.
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