Perunitweight

Perunitweight is a term used in multiple disciplines to describe the weight assigned to a single unit of a material or item. It is not a single standardized physical quantity; its meaning depends on context, including engineering, logistics, or quality control.

In physics and engineering, weight is the force due to gravity acting on a mass. If weight is considered on a per-unit basis, dividing weight by the corresponding mass yields the local gravitational acceleration g. When weight is expressed per unit volume, the quantity is called the specific weight or gamma (gamma = rho g), a parameter widely used in hydraulics, geotechnical engineering, and related fields to compute forces and pressures.

In logistics and manufacturing, per-unit weight typically refers to the weight of a single item, component, or package. This metric is used to price shipping, determine freight costs, set handling fees, and manage inventory. For example, a product with a mass of 0.5 kg per unit has a per-unit weight of 0.5 kg, which may be multiplied by a rate to estimate shipping charges.

Calculation commonly involves measuring the total weight W of a batch and dividing by the number of units N: per-unit weight = W / N. If all units are identical, this yields the weight per unit. If unit weights vary, a weighted average may be more appropriate for estimating the per-unit weight.

Related concepts include density (mass per unit volume) and specific weight (weight per unit volume). Per-unit weight thus serves as a practical normalization tool across pricing, logistics, and engineering calculations.