Approved Weighing Machines

Scales approved by Trading Standards for buying and selling precious metals 



Approved for use in trade means buying or selling on a value-for-weight basis. This applies to any transaction, whether in a shop, pawnbrokers, antiques fair, market or even a boot sale, even if you do not regard yourself as a trader. So if you are offering to buy or sell anything by weight, you MUST use an approved balance, it is the law; if you are not buying or selling by weight, then there is no need to read on.

In this article I refer to Weights & Measures Inspectors - these are Trading Standards Officers who happen to deal with weights and measures.

BREXIT UPDATE FOR 2021 / 2022...2023

When we joined the EU and agreed to abide by EU standards (with the "CE" approval mark) the cost of approved scales fell by half, quite literally overnight. Now that we have left the EU we will be reverting to UK standards (a new "UKCA" approval mark). The government had aimed to complete this process by January 2022 but due to non-action have now postponed it until January 2023.  

Our current models are EU-approved, they will still be approved after 1 January 2023. So you can buy an EU-approved scale from us now (you don't have to wait until 2023) and it will be approved now and forever more.

However, as from 1 January 2023 suppliers (such as ourselves) must not sell EU-approved scales.

So far (Christmas 2021):

  • the introduction of the new UK ("UKCA") mark is subject to new rules which the government haven't yet announced, and 2022 will be a transition period subject to special rules...which haven't yet been announced.
  • for the manufacturers/importers the "transfer of approvals" from the EU to UK standards will cost few thousand pounds per model, so price rises are inevitable (they are still saying, "We have no price rises planned" - that is because they can't plan, they have no information about what is going to happen next or how much it will cost).
  • the lack of planning and total lack of clarity means that for suppliers such as ourselves, we must not be left with any old stock on 1 January 2023 so as we go into 2022 we will only be getting these to special order. 


If you buy or sell by weight (i.e. an amount of money per gram or per ounce) then you are using the balance 'in trade' and it must be approved. However, if you use it as part of your valuation but do not base the value on weight (e.g. jewellery where the main value is in gemstones, diamonds or antique value) then you do not need an approved balance - you are still a trader, but you are not using it 'in trade'.

Any Weights & Measures Inspector will notice if you are buying or selling by weight, even if you pretend otherwise. He can see whether you are calculating a price based on weight or if you are calculating the price by carefully evaluating gemstones and hallmarks.

In the past I said that auctions were an 'iffy' area. Following a 2½ hour meeting with a Weights and Measures Inspector, I can now clarify the position: an auction house must use an approved balance if the item description includes the weight. 

At fairs and markets the same laws apply. Traders buying scrap must use an approved balance. You may say to yourself, "But nobody uses an approved balance in my market, and never has done!" Maybe everyone unloading at the market parks on a double yellow line. I can only tell you about the law, not how it is enforced.


The actual standards for Weights and Measures are determined by the National Measurement Office who study the law, look at the science, and issue guidelines to Weights & Measures Authorities. The law is enforced by Weights and Measures Inspectors, they work for the Trading Standards department at your Local Council. You can find them by going to Trading Standard's Home Page (enter your postcode in the box at the top and click 'go'). If you wish to study the law yourself, see the Weights & Measures Act 1985 and its many amendments. Then, if you disagree with an inspector, you may accept his offer to have the matter settled in court. Of course, Brexit has caused many complications, see the latest information.

Each Local Council's Trading Standards Department enforces the law at a local level. So whilst the law is consistent, each Local Council has its own priorities regarding enforcement (i.e. they might have more important things to do)


First, the easy bit. A weighing machine used in trade must be stamped with a special sticker. These stickers are seals that are carefully placed over vital screws on the balance, if you break the seal and touch the screws (to open or recalibrate the balance) it will no longer be approved.

There are four Classes (grades) of approved balance:

  • CLASS 4 need not concern you, it is for heavy items such as heavy goods vehicles
  • CLASS 3 need not concern you, it is for general goods, e.g. food (anything from herbs to bags of fruit)
  • CLASS 2 is for items that have a high value per gram, specifically precious metals (including silver)
  • CLASS 1 need not concern you, it is for scientific applications, e.g. for weighing down to 0.0001g


- Complication No. 1: 1g or 0.1g or 0.01g?

When you buy an approved CLASS 2 balance the manufacturers might give you its specification as, for instance, 6000g in steps of 0.1g. What they don't tell you is that once it's approved, you are not supposed to use that last decimal place when used "in trade". So, for instance, having spent hundreds of pounds and thinking you will be weighing down to 0.1g you will discover that the balance now has a red cross painted over that last decimal place so that it only reads to the nearest 1g. (though the 0.1g will still be visible under the red cross). For your own purposes (away from customers, for your own valuation purposes) you may weigh to 0.1g, but when buying by weight you are supposed to ignore the 0.1g and work to the nearest 1g.

All the balances we sell have this two-tier system, a more sensitive reading for your own use and a less sensitive reading for buying precious metals by weight.

- Complication No. 2: buying or selling?

If you are selling by weight, the customer must be able to see the display and you must never use a balance with a "crossed out" digit, but you can use it to price items by weight (ignoring that "crossed out digit") out of sight of the customer.

Our balances do not have a display facing the customer, therefore they can only be used for buying by weight but not for selling by weight However, we can get (to special order) a front-facing display, please ask -  you can then buy and sell by weight.

Why so complicated?? - because when the law was made, it was assumed that retailers sold goods by weight (mostly groceries) but it never occurred to the law-makers that a trader might buy by weight, and so the words "and buying" were not included in the law.

- Complication No. 3: balances calibrated by area

Some CLASS 2 balances are calibrated for a particular area (usually a town, sometimes a full postcode). This is to allow for variations in gravity. So if, for instance, you use a balance in central Liverpool, then it will be calibrated for central Liverpool, you can't legally use it anywhere else.

We have a simple solution to this. We no longer sell this type of approved balance. Our approved balances can be used anywhere.



Check your balance whenever it is moved. If you work at fairs and markets, that includes moving to a new venue, it also includes moving the balance from one side of the stall to the other. Even if the balance lives on a shop counter and is never moved (not even by a few inches) it is wise to check it every few weeks.

To check it, buy a weight, any weight that is near (or at) the top of the balance's range. Switch the balance on, place the weight on the platform, check the reading. It really is no more complicated than that.