Commodity guide · generators
Portable generators typically rate class 70 - 92.5 (10 - 22.5 pcf); large standby units on skids are denser and can rate class 65.
Generators are engine-dense machines: portable units in retail boxes usually measure 10 - 18 pcf (class 70 - 92.5), while industrial standby generators bolted to skids are heavier per cube and can reach class 65.
Worked example. A boxed portable generator: 30 × 24 × 24 in, 210 lb. That is 10.0 cu ft and 210 lb → 21.00 pcf → class 70. Run your own numbers →
Relevant class pages: class 70 · class 85 · class 92.5.
Drain fuel completely before tendering - fuel in the tank makes the shipment hazmat and most LTL carriers will refuse or re-bill it. Bolt or band the frame; a shifted generator damages everything around it.
Related: the full class chart · density calculator · how NMFC codes work.