Why a big box costs more to ship, even when it weighs nothing

There is one number on the consignment form that gets filled in carelessly more than any other, and it is the one that decides what the buyer is charged: the size of the box.

One listing went live with dimensions of 100 x 100 x 100 centimetres. Inside it was a helmet. The courier would have billed it as a 167 kilogram parcel.

Volumetric weight, and the arithmetic behind it

Couriers do not bill on weight alone. They work out two figures and charge the larger:

• the parcel's actual weight, and
• its volumetric weight, which is length times width times height in centimetres, divided by 6000.

A helmet weighs about 1.5 kilograms. A sensible helmet box, say 40 x 40 x 40 centimetres, gives 64,000 divided by 6000, which is about 10.6 kilograms. That is the figure that gets used, not the 1.5.

The reason makes sense from the courier's side: what they sell is space in a van, and a large box full of air takes as much of it as the densest parcel you could pack.

One detail that catches people out: couriers round up, to whole kilograms. A 1.2 kilogram parcel is billed as 2. So three helmets are not three times 1.2 rounded once, they are three parcels each rounded up on its own.

Why the measurements are required

Weight and the three dimensions are required at the details step, and that is the only required field in this form that is not there for a safety reason.

A helmet's production date may be left blank: it is a disclosure, and when it is missing the listing says so and the buyer decides. A parcel size is not a disclosure, it is an input to a price. Left out, the shipping quote comes from a category default. Gearkeun books the courier and pays the provider, so the gap no longer comes out of the seller's margin the way it once did -- but that number is still what the buyer is charged at checkout, and a quote that is badly wrong is a parcel the courier re-weighs at the depot.

So measure the box, not the object. What gets paid for is the carton that travels, bubble wrap and empty corners included.

The origin address decides the rest

Shipping is quoted from the seller's origin address to the buyer's delivery address. Not from any warehouse, because there is none: the item stays with the seller until it sells, and leaves from there.

The difference is real. The same 6 kilogram parcel, to the same door in Pondok Pinang, South Jakarta:

That is why an origin address is required before a listing can go live. Without one the quote is measured from the wrong place, and nobody can see it from either end.

The courier is booked, not walked to

At the shipping step a seller ticks which couriers they can actually use. Nothing is ticked to begin with, and that is deliberate: if every chip started on, people would scroll past and quietly promise couriers whose agents are not in their town.

Buyers only see the couriers you ticked, and they pay for a specific service rather than for "shipping" in general. By the time the order arrives the courier has already been decided by that payment, and what is left for you is one button: book the courier.

The tracking number comes from the courier, not from a field. A number typed by hand is connected to no tracking system at all, so nobody can watch the parcel move and the order never learns it arrived -- including the clock that releases the money to the seller.

By default the courier collects from your origin address. Some carriers also take a drop-off at their agent, and that choice appears only where the carrier being used actually accepts one. The shipping is paid up front through Gearkeun, so there is nothing for you to pay at a counter.

In short

Measure the box, not the object. Put in the origin address you really post from. Tick the couriers that genuinely operate in your town. Those three decide whether the shipping figure on the buyer's screen is close to reality.

If you are just starting, the full sequence is in how consignment works at Gearkeun.