Three hauls, three merge timings, three totals

Meet the three buyers and their three hauls

Three hauls, three decisions and one formula underneath them. The first buyer wants three light items for personal use and nothing else. The second buys twelve identical hoodies to resell and needs every retail bag intact. The third holds fourteen small items from several stores and feels no attachment to the boxes they arrived in. Each haul gets a merged option and an unmerged option, priced in billable kilos at divisors 6000 and 8000 rather than in currency, because we do not quote rates.

Haul one contains a tee, a hoodie and a cap. On the scale the tee reads 0.25 kg, the hoodie 0.7 kg and the cap 0.15 kg, for 1.10 kg of goods. Sent separately each item gets its own outer packaging: the tee in a 30 × 24 × 6 cm bag, the hoodie in a 32 × 26 × 10 cm bag, the cap in a 24 × 20 × 8 cm box. Those three outsides are the reason the unmerged option costs more than the goods alone suggest.

Twelve hoodies at 0.7 kg each make up the second haul, which is 8.4 kg of goods with packaging that must survive the trip, because a reseller sells the bags as much as the garment. Packed as shipped, the twelve occupy two cartons: one at 50 × 40 × 35 cm and one at 50 × 40 × 20 cm. Folding is allowed here, bag removal is not, so the volume can fall through folding and through choosing a single carton instead of two.

Fourteen small items totalling 3.2 kg form the third haul, each in its own retail box, sourced from different stores. Left as they arrive, the collection packs into one 60 × 45 × 45 cm carton and no smaller, because rigid retail boxes do not nest. Discarding the retail packaging and bagging the goods instead allows a 55 × 40 × 25 cm carton, with garments taped flat where the fabric permits. The choice between those two boxes is the largest single decision in this article.

One rule governs all three hauls: chargeable weight is the larger of the scale reading and the volume divided by the divisor, with each dimension rounded up to a whole centimetre. Every number below is arithmetic on the dimensions just given, computed at divisors 6000 and 8000. Nothing in the comparison depends on a rate, a route or a carrier, so the merged-against-unmerged result survives any change in price; only a currency figure would move.

Run the small haul and the reseller haul

Sent separately, the first haul becomes three parcels. The tee bag measures 4,320 cubic centimetres and produces 0.72 kg at divisor 6000 and 0.54 kg at 8000, so it bills on volume either way. The hoodie bag measures 8,320 cubic centimetres and produces 1.39 kg and 1.04 kg against a 0.70 kg scale reading, so volume bills again. The cap box measures 3,840 cubic centimetres and produces 0.64 kg and 0.48 kg against 0.15 kg. The three totals are 2.75 kg and 2.06 kg on three separate labels.

Merged, the same 1.10 kg of goods goes into one 32 × 26 × 16 cm bag measuring 13,312 cubic centimetres. That produces 2.22 kg at divisor 6000 and 1.66 kg at 8000, both above the 1.10 kg scale reading, so volume bills at either divisor. The merged path beats the separate path in both cases, 2.22 against 2.75 and 1.66 against 2.06, and it converts three labels into one. The saving comes from the two outer bags that no longer exist rather than from anything done to the goods.

Cartons carry the second haul if it travels as shipped. The 50 × 40 × 35 cm carton measures 70,000 cubic centimetres and produces 11.67 kg at divisor 6000 and 8.75 kg at 8000 against a 5.0 kg scale reading. The 50 × 40 × 20 cm carton measures 40,000 cubic centimetres and produces 6.67 kg and 5.00 kg against 3.4 kg. Rounding each carton before adding gives totals of 18.34 kg and 13.75 kg on two labels, and volume bills in all four of those comparisons.

Folded into one 60 × 45 × 40 cm carton, the same twelve hoodies measure 108,000 cubic centimetres and produce 18.00 kg at 6000 and 13.50 kg at 8000 against the unchanged 8.4 kg scale reading. The gain is 0.34 kg at one divisor and 0.25 kg at the other, plus one fewer label. That is the whole saving available to a reseller who cannot remove the retail bags: the carton’s geometry sets the volume, and folding changes that geometry less than intuition suggests.

Run the multi-item haul with and without its retail boxes

Haul three shows the other extreme. With every retail box kept, the 60 × 45 × 45 cm carton measures 121,500 cubic centimetres and produces 20.25 kg at divisor 6000 and 15.19 kg at 8000, against only 3.2 kg on the scale. The goods are a fifth of the billed figure, and the rest is cardboard and air that arrived from fourteen different stores and was never meant to travel together.

With the retail packaging discarded, the same goods fit a 55 × 40 × 25 cm carton measuring 55,000 cubic centimetres, which produces 9.17 kg at divisor 6000 and 6.88 kg at 8000. The difference is 11.08 kg at one divisor and 8.31 kg at the other, and it is decided before the box is closed. No other single decision across the three hauls comes close to that swing, and none of it requires a rate to evaluate.

Timing then becomes concrete. Items still travelling cannot be packed into a box that has already been closed, so a merge timed too early locks a volume the last item may not fit, while a merge timed too late means paying storage on goods that are ready and waiting. Neither error shows up as a line on an invoice; both show up as a box that was bigger than it needed to be, or as days spent stored when the haul could have been moving. A merge date chosen before the last tracking number goes live is a guess wearing a schedule.

Compare cost and risk across the three totals

Totals for the first buyer are 2.22 kg merged against 2.75 kg separate at divisor 6000, and 1.66 against 2.06 at 8000. The gain is 0.53 kg and 0.40 kg plus two fewer labels and two fewer handovers. The risk runs the other way and is worth naming before it is accepted: one parcel holding the whole haul is exposed to a single loss, a single customs question and a single failed delivery, where three parcels would fail independently.

For the reseller the totals are 18.00 kg against 18.34 kg at 6000, and 13.50 against 13.75 at 8000. The gain is real and small. The risk differs in kind, because folding a hoodie that is meant to be resold creases the fabric, and a crease that does not hang out is a discount on the resale price, which is a cost this arithmetic cannot express. On this haul the merge is nearly free and the packaging decision carries the loss.

Buyer three lands on 9.17 kg against 20.25 kg at divisor 6000, and 6.88 against 15.19 at 8000. The risk sits exactly where the saving sits: discarding retail packaging removes the item’s ability to be resold as new and weakens any return argument that depends on the goods going back in saleable condition. One act produces an 11.08 kg saving and an unquantified exposure, which is the honest shape of the trade.

An ordering rule follows from the three comparisons. Measure the merged box first, because the merged box is what will be measured by somebody else. Establish the divisor before accepting a total, since a move from 6000 to 8000 changes every figure here by a quarter. Where no divisor is published, price the merged option at both values and plan on the worse one. Then decide, and write both totals beside the order number so the decision can be reviewed later.

Timing enters through volume rather than through price. A parcel that is merged on the day the last item lands contains everything the haul was meant to contain, and a parcel merged a week early contains less; the difference is a second shipment that pays its own minimum. Holding a haul for a 0.4 kg gain is not worth the storage, while ignoring the 11 kg swing on a fourteen-item haul is the more expensive mistake of the two. Merge when every item has landed, when the storage position is still free, and when the box size is still a choice rather than a given.