Void Movements in the Domestic Parcel Network: First National Estimates for 2016–2025, with a Note on the Statistical Treatment of Goods

The box was too big for what was inside it. It was the right size for what was being sent, which was the empty space. We report first national estimates of void movement in the domestic parcel network. Freight is accounted in tonne-kilometres, so the quantity that constrains the network has never been counted in the national account. Vans fill their space long before they reach their weight limit, and carriers have charged for parcels by volume rather than weight for decades. Measuring 41.8 million parcels at four city cordons between 2016 and 2025, we find that 62.4% of the volume the network moves is empty space (95% CI $61.8$–$63.0$). The void is not a residue of packing. The dimensions of an item explain 19% of the variation in the volume of the box around it; the routing lane, on its own, explains 81%. Where a product’s packed volume was cut by a third at a manufacturing changeover, its box did not move. A container whose size does not depend on its contents is not a container. We then inducted 1,200 parcels containing nothing, each matched to a parcel that was not empty. They were held, referred, and returned undamaged, marked as having no declared content. We propose that enclosed volume be published as a headline series and that goods be carried as a memorandum item. The box is not the packaging. The thing inside it is.