Weight certificate: what it proves and who issues it

A weight certificate is a statement of how much cargo was weighed, by which method, where and when. It proves that one determination. Whether the figure binds buyer and seller is for the sale contract to decide, and the bill of lading weight is a separate figure with a different author.

What a weight certificate proves

What the figure means for the price is set by the contract. GAFTA form 100 (feedingstuffs in bulk, CIF and C&F, edition effective 1 July 2026) settles on gross delivered weights at the time and place of discharge, unless the parties agree otherwise (clause 15). The seller then pays for any shortfall below the bill of lading weight and the buyer for any excess, at contract price, unless the pro-rata clause applies (clause 16). If the parties instead make weights final at loading, on the certificate of a GAFTA approved superintendent chosen and paid for by the seller, that deficiency clause falls away.

So one cargo can carry two weight certificates, one per port, and the contract says which counts. Quality has its own documents; see certificate of analysis versus certificate of quality.

Who issues a weight certificate

In practice nobody signs a weight certificate as a person. When a weighbridge is used, the terminal gives it out, and for liquids the weight is established from the shore tank measurement; the weight certificate then just shows how that figure came about, with the scale, the method and the numbers. Containers and road trucks are weighed over a weighbridge, which gives gross, tare and net per unit with the weighing ticket.

GAFTA Weighing Rules No. 123 (contracts from 1 January 2022; still current on gafta.com in September 2026) leave the weighing to dock authorities, public sworn weighers, weighers recognised by the local public or dock authorities under the custom of the port, or weighers approved by the superintendents (rule 1:1). The parties and their approved superintendents get full access to the equipment, may oversee every check and can ask for all tickets and printouts (rules 1:2 and 1:10).

The certificate that makes weights final at loading under form 100 comes from a superintendent on the GAFTA Approved Register. To be listed, a firm needs Category C membership, works to Rules 123 and 124, and holds either GAFTA's own standard or an ISO/IEC 17020 Type A accreditation with the appropriate scope; see ISO 17025 versus ISO 17020.

Operium Solutions does not issue weight certificates and is not accredited. The template with this article is our own blank form.

The method belongs on the weight certificate

GAFTA 123 does not treat every method alike:

Method	Position under GAFTA 123
Hopper scales	accepted if certified to accuracy class 0.2 or Class III/IIIL; class 0.5 only with both parties' written acceptance (rule 2:4)
Road weighbridge	every truck weighed gross and tare, no double- or tri-axle weighing; a truck weighed once when work stops is weighed again when it resumes (rule 7)
Belt weighers	not wholly accurate; only where no suitable hopper scale is available, with both parties' written acceptance and further conditions, otherwise for information only (rule 3)
Draft survey	not wholly accurate; not acceptable for contractual purposes unless both parties explicitly agree in writing (rule 5)
Liquids	the rules above, otherwise the custom of the trade or port (rule 9)

For belt weighers, crane scales and draft surveys the method must be on the certificate. For liquids, rule 9 applies the rules above, otherwise the custom of the trade or port; our template offers shore tank and flowmeter as entries, and the one used goes on the certificate. How a ship's figure is built up is covered in what is a draft survey; tank figures in the ullage report and sounding tables.

The equipment matters as much. Its latest check certificate or log must be available on request (rule 1:4), and where a national tolerance exists, it applies (rule 1:8). If checks cannot be made or are refused, or the equipment proves out of tolerance, the parties have to agree the weight, failing which it may be referred to arbitration under GAFTA 125 (rule 1:11). Our template has a line for the equipment and its latest verification.

Weight certificate versus the bill of lading weight

The bill of lading is a receipt, not a weighing. Under the Hague-Visby Rules it shows the quantity or weight as furnished in writing by the shipper (Article III rule 3(b)); the carrier need not state a weight it has reasonable grounds to doubt or no reasonable means of checking. The shipper is deemed to guarantee that figure to the carrier (rule 5). Against a third party who took the bill in good faith, the carrier cannot prove that it received something else (rule 4). The mate's receipt the bill is made out from, and how its remarks carry over, is covered in mate's receipt vs bill of lading.

The weight certificate is the measurement that can test that declared figure. At discharge, the outturn weight is compared with the bill of lading weight; see the outturn report and cargo shortage. Britannia P&I calls it unfair to reconcile a shore scale with a draft survey, two distinct methods, and wants the charter party to say which figures count. When a gap amounts to a shortage, and against whom, is covered in cargo claims in bulk shipping.

What the certificate does under a documentary credit

Under a letter of credit the bank takes no responsibility for the quantity or weight a document represents (UCP 600 article 34); it checks the issuer, that the content does not conflict with the credit or the other documents, and the quantity tolerance. The rules are set out in letter of credit and the inspection certificate.

A buyer who wants a named weigher, method or place has to write it into the credit.

Worked example from the template

The example in our Excel template is fictitious: soyabean meal delivered by truck from a terminal, each truck weighed gross and tare, as rule 7 requires, here on the same weighbridge. Net is gross minus tare per ticket.

Truck	Gross (kg)	Tare (kg)	Net (kg)
1	43,180	14,620	28,560
2	42,950	14,480	28,470
3	43,410	14,710	28,700
4	42,875	14,555	28,320
5	43,020	14,600	28,420
Total	215,435	72,965	142,470

142,470 kg is 142.470 tonnes of 1,000 kg, the unit form 100 prices in (clause 3). The tickets are whole kilograms, so the three decimals are exact.

Based on the working practice of our sector specialist: 25 years in the port, 20 of them as a cargo surveyor. The weight certificate usually comes from the terminal when a weighbridge is used; a shore tank measurement is itself the determination of weight.

A certificate that gives only a total invites the first question in any dispute: weighed how, and on what? One that names the bridge, its last check and the gross and tare per ticket leaves less to argue about.

From weighbridge to file

FOSS is software for inspection companies and the port, with a sector specialist at the table. Measurements are entered once, offline on board if need be, and nine report types come from that input. Outturn is set per medium against the bill of lading weight, with an automatic protest flag above a 0.5% shortage; the person on the quay decides what follows. To see it with your own figures, get in touch; we start with a free QuickScan.