Supplymo research edition
Original research from the supply side
Where the shipping weight on a 1688 listing comes from
Chargeable weight decides what a shipment costs, and it is computed from two inputs: a weight and a set of dimensions. We looked at what 120 top-ranked 1688 listings actually display for those two inputs, and where each figure says it came from. All 120 showed a shipping block. 117 of them carried a weight the merchant typed in themselves.
It does not say any displayed weight is wrong. Nothing was weighed. A merchant-entered weight can be exactly right, and a measured one can be stale.
Liam Cai · Founder, Supplymo
Published 15 August 2026 · Collected 2026-08-12 · Yiwu, China
Evidence figure · Shipping-weight provenance
117
of 120
Merchant typed it in
- Measured by a fulfilment centre
- 3
- No source label shown
- 1
n = 120 listings. Collected 2026-08-12. Non-random sample: 12 keyword searches, 10 platform-ranked rows each. All 120 listings displayed a shipping block.
Collected
2026-08-12
Evidence
Version 1 · 120 listings
Sample status
Non-random · method and row unit stated
Reuse
CC BY 4.0 · 8 stated limits
Study reading
The number your freight quote is built on was typed in by hand
Volumetric weight is not an opinion. A forwarder takes length by width by height, divides by a volumetric divisor, compares the result to actual weight, and bills the larger of the two. That arithmetic is well understood and rarely disputed.
What gets less attention is where the two inputs come from. In this sample the weight on 117 of 120 listings was labelled as merchant-entered. Only 3 carried a weight labelled as measured by a fulfilment centre. A merchant-entered weight is not automatically wrong; the returned field simply does not show an independent measurement behind that value.
Study reading
The dimensions gap is wider than the weight gap
A weight field existed on nearly every sampled response. Complete dimensions appeared on 45 of 120; 74 returned a dimensions field that was zero or partly filled, and one response omitted the dimensions field.
For bulky, light goods, volumetric weight can exceed actual weight. This study did not calculate chargeable weight or determine which side would win for these rows. When complete dimensions are unavailable, the volumetric half of the calculation cannot be completed from the returned listing data alone.
Study reading
One listing, several weights
108 of 120 listings carried more than one weight across their SKU rows. Often that is legitimate: a listing may run from a small size to a large one, and the weights should differ.
The practical problem is matching the figure to the exact SKU. This study did not measure which row buyers or quoting tools select. In the widest case, the heaviest returned SKU weight was 53.7× the lightest returned SKU weight on the same listing, so substituting one variant's weight for another can materially change an estimate.
Study reading
What a buyer can do with this before paying
Ask which SKU the quoted weight belongs to, and request dimensions in writing when complete values are unavailable. Keep that answer with the quote so it can be checked later against the carton.
The wider point is about the shape of a quote, not about any individual seller. If a freight figure was derived from listing data, whoever is relying on it deserves to know which parts of it were measured and which parts were typed in.
Research boundary
What this study cannot tell you
- BoundaryIt does not say any displayed weight is wrong. Nothing was weighed. A merchant-entered weight can be exactly right, and a measured one can be stale.
- BoundaryIt does not say a platform or a seller has done anything wrong. Displaying a self-reported weight is normal practice across marketplaces.
- BoundaryIt is not a random sample. The rows come from the first page of 12 keyword searches, and the platform ranks that page. Highly ranked listings are, if anything, more likely to carry complete shipping data than an average listing.
- BoundaryIt covers bulky English-language home goods on the cross-border distribution channel, on one day. Dense, regulated or made-to-order categories may look different, and no trend is claimed from a single observation.
- BoundaryThe rows are listings, not distinct suppliers. Seller identity is deliberately not collected, so one shop may appear more than once.
Questions readers ask
Read the finding without over-reading it
Does this mean 1688 shipping weights are unreliable?
No. It means we can say how the API labelled the source of a figure, not whether the figure is accurate. 117 of 120 sampled responses labelled their weight as merchant-entered; they did not show a fulfilment-centre measurement label for that value.
Why do missing dimensions matter if the weight is shown?
Because volumetric weight needs all three dimensions and can exceed actual weight for bulky, light goods. Complete dimensions were unavailable on 75 of 120 sampled responses: 74 returned zero or partial values and one omitted the field. This study did not calculate which weight would determine a freight bill.
How was the data collected?
Through 1688's own read-only keyword-search and product-detail API, in a single session on 2026-08-12. No orders, messages, inquiries or other write operations were involved. The full row-level data and the method are downloadable on this page.
Can I reuse the data?
Yes, under CC BY 4.0, including commercially. The CSV, the evidence JSON with the method and limits, and a copyable citation are all on this page. If you need a cut that is not published here, ask.