Furniture and glassware look like two unrelated categories, but they share one thing in NMFC classification: a wide density spread, with the same base code splitting into several density tiers and very different classes. Glass bottles, carboys, and jars (NMFC 87700) can, in theory, land anywhere across the full class 50 to 400 range depending on measured density, and mattresses (NMFC 79550) — bulky but not especially heavy — tend to sit at a higher class year-round. Measuring actual density from real dimensions (including packaging and any overhang) beats assuming a class from memory.

Mattresses, sofas, and box springs (under codes like NMFC 79550) are typically large in volume but relatively light, which means low density — and low density generally means a higher class than a similarly-sized solid item. Estimating the class from experience instead of actual measurement is an easy way to underquote and get hit with a reweigh/reclass adjustment after pickup.
Glass bottles and jars (NMFC 87700) are density-tiered across the full class 50 to 400 range. Beyond density, whether the packaging has adequate cushioning and whether it's custom-packed can affect how the carrier handles the shipment and, if there's a damage claim later, how it gets resolved. For glassware, it's worth documenting the packaging and cushioning used in case a claim comes up.
Metal furniture components — stands for TVs or audio equipment, for example (NMFC 178715) — typically fall under a metal-goods code, not the same code as wood or upholstered furniture bodies. For mixed-material furniture sets, describe by the dominant material or declare components separately rather than using one generic description that invites a carrier re-classification on arrival.
The codes below are verified against ShipMay's own NMFC database and are meant to illustrate classification logic — the exact code and class that applies to your shipment depends on your actual commodity description, measured density, and the carrier's own review:
| Commodity | NMFC Code | Typical Class Range |
|---|---|---|
| Mattresses, upholstered box springs, or waterbeds | 79550 | 300 |
| Portable folding lap desks | 57145 | 125 |
| Metal TV/audio/phonograph stands | 178715 | 92.5 |
| Bottles, carboys, or jars (non-cut glass) | 87700 | 50 – 400 (13 density tiers) |
| Wooden store display rack or stand parts | 154675 | 70 |
Materials and packaging vary widely within "furniture," so a generic label can map to very different codes. Recommended approach: search by specific commodity — mattress, lap desk, glass jars — in the NMFC Lookup tool rather than searching "furniture"; measure the actual footprint including packaging and overhang; for mixed-material sets, describe by the dominant material or declare items separately; and for glassware, keep a record of the cushioning and packaging used. When in doubt, send ShipMay the commodity, weight, and dimensions — the final code and class are still subject to the carrier's own review.
NMFC code guides for other common commodity categories: electronics, food and packaging, building materials and metal, auto parts.