Determining the correct freight class is essential for accurate shipping costs and unexpected fees. Freight class is a standardized system in North America (typically NMFC-based) that categorizes goods based on transportability.
| Class | Density Range (lbs/cu ft) | Example Items |
| 50 | ≥50 | Machinery, bricks |
| 55 | 35-50 | Ceramic tiles, cement |
| 60 | 30-35 | Car parts, bottled beverages |
| 65 | 22-30 | Auto parts, furniture |
| 70 | 15-22 | Cabinets, cast iron stoves |
| 77.5 | 13-15 | Tires, Mattresses |
| 85 | 12-13 | Crated machinery |
| 92.5 | 10-12 | Computer monitors |
| 100 | 9-10 | Glassware, canvas |
| 110 | 8-9 | TVs, large appliances |
| 125 | 7-8 | Small appliances, boxes of books |
| 150 | 6-7 | Lightweight fixtures |
| 175 | 5-6 | Clothing, lampshades |
| 200 | 4-5 | Bagged goods, foam products |
| 250 | 3-4 | Ping-pong balls, empty containers |
| 300 | 1-3 | Life jackets, empty drums |
| 400 | ≥0.5 | Down feathers, insulation |
| 500 | ≥0 | Aircraft parts, Artificial flowers/plants |