Trade approved scales in the UK: what Class III means and when you need one

What is a trade approved scale?

A trade approved scale is a weighing instrument whose design has been type approved and whose individual unit has been verified against the Non-automatic Weighing Instruments Regulations 2016, so its readings may be used to set a price in a commercial transaction.

You can tell one from the data plate. It carries:

• a UKCA or CE mark
• a boxed M (the metrology mark) with the last two digits of the year of verification
• the number of the approved body that carried out the assessment
• the accuracy class, normally Class III for shop, wholesale and warehouse use

"Legal for trade" is the US term for the same thing. UK buyers say trade approved, Class III approved, stamped, or CE-M and UKCA-M. They all mean a scale that Trading Standards will accept for selling by weight.

Our launch range is check-weighing only: check-weighing platform scales and pallet scales for goods-in and despatch. They are not trade approved. If you need an approved model, ask us on WhatsApp and we will quote one on request.

Do I need trade approved scales? The Weights and Measures Act and NAWI Regulations

You need trade approved scales to sell by weight, that is when the weight reading determines what someone is charged. The Weights and Measures Act 1985 sets the principle and the Non-automatic Weighing Instruments Regulations 2016 (the NAWI Regulations) set the technical and marking rules. Internal weighing for your own records, quality or production does not need approval.

The test is simple. If the number on the display becomes a number on an invoice, the scale must be approved. If the number only goes into your own records, it need not be.

What is a Class III scale?

A Class III scale is a medium accuracy weighing instrument with between 500 and 10,000 verification divisions and a verification interval e of at least 0.1 g. It is the class used for almost every shop, wholesale and warehouse scale that sells by weight.

The four accuracy classes under the NAWI Regulations are:

• Class I, special accuracy: laboratory balances
• Class II, high accuracy: jewellery and pharmacy scales
• Class III, medium accuracy: retail, wholesale, industrial and platform scales
• Class IIII, ordinary accuracy: 100 to 1,000 divisions, permitted for trade only on ballast, landfill and waste

Class IIII is not a shortcut to selling groceries by weight. Anything other than ballast, landfill or waste needs Class III or better.

If you search for Class III scales you will see medical pages first. Class III there refers to a different scheme for medical devices and has nothing to do with weighing for trade.

Class III scale accuracy: e, d and tolerance

On a trade approved scale the figure that matters is e, the verification scale interval. It is the legal division. d is the display division, the smallest step the indicator shows.

Worked example: a 300 kg scale with e of 100 g has 3,000 verification divisions, which sits inside the 500 to 10,000 range for Class III. On an approved scale e and d are normally equal.

A check-weighing scale can show a finer d, such as 50 g on a 300 kg platform. That does not make it more legal. Without type approval and verification the reading has no standing when selling by weight, however fine the display.

Tolerance is the permitted error at verification and in use, expressed in multiples of e and stepped by load. It is the reason an approved scale is checked at several points across its range, not just at full capacity.

How to check a scale is trade approved: CE-M and UKCA-M marks

Read the data plate. A trade approved scale shows a UKCA or CE mark, a boxed M with a two-digit year, the approved body number and the accuracy class. If the plate lists only capacity and division, the scale is for check-weighing and cannot be used to sell by weight.

• Crown stamp: older units verified under the previous UK scheme carry a crown; it remains valid until the scale is repaired or fails inspection.
• Six-pointed star: the scale has been rejected by an inspector and must not be used for trade until re-verified.
• Green M sticker: the metrology mark used under the earlier regulations before 2016. Scales that carry it remain valid for trade while they stay verified and in good repair.

Is a CE-M scale still legal in Great Britain after 2025?

Yes. Great Britain recognises CE marking for non-automatic weighing instruments indefinitely under the Product Safety and Metrology etc. (Amendment) Regulations 2024. A scale marked CE-M and a scale marked UKCA-M are equally valid for trade. There is no need to replace CE-M scales that are in good order.

Calibration, verification and re-verification

Calibration is not approval. Calibration compares the scale against test weights and produces a certificate that shows how far it reads from true. Verification is the legal check that puts the boxed M on the plate. A calibrated scale is not automatically legal for trade, and an approved scale still needs routine checks.

How often should industrial scales be calibrated? There is no fixed legal interval. Common UK practice is once a year, or every six months for heavy use, wet areas or platforms loaded with a pallet truck.

Re-verification is mandatory after any repair to the load cells or the indicator on an approved scale. It may be carried out by an inspector of weights and measures, an approved verifier or an approved manufacturer. Until it is done, the scale may not be used to sell by weight.

For check-weighing scales the same practical schedule applies. A goods-in scale that drifts costs you money on every delivery you accept.

What happens if Trading Standards find non-approved scales in use?

Trading Standards officers may inspect weighing equipment used for trade at any time, without notice. If a scale in use for selling by weight is not approved, or has been repaired without re-verification, the officer can mark it as rejected and require you to stop using it.

Outcomes range from a notice giving time to replace or re-verify the equipment, through fines, to prosecution in serious or repeat cases. Selling short weight from a non-approved scale is a separate offence from using the scale itself.

The simplest protection is to keep approved scales on the counter, check-weighing scales in the warehouse, and never mix the two jobs.

Weighing scales for cash and carry and wholesale: which do you need?

Two types. One Class III trade approved platform or bench scale for anything sold loose by weight, such as rice, pulses, spices, nuts or meat priced per kilo. One check-weighing floor or pallet scale for deliveries and despatch, where the reading goes into your own records rather than onto an invoice.

At launch we supply the second type. A 300 kg platform scale covers goods-in checks on cartons and sacks, a 600 kg platform scale takes drums, half pallets and loaded trolleys, and the 2000 kg pallet scale weighs full pallets. Approved counter scales are quoted on request.

Which scales does a food distributor need?

A food distributor needs a stainless steel top and an IP rating that survives wash-down, plus Class III approval on any scale that sets a price. A pallet scale at despatch confirms the weight on every consignment before it leaves.

Tell us where the scale will sit, whether it will be hosed down, and whether the reading will ever appear on an invoice. We will confirm the specification for the model you need before you order.

IP ratings for warehouse and food scales: IP65, IP67 and stainless steel

IP65 is the practical minimum for a warehouse scale: dust tight and protected against water jets. IP67 or IP68 is needed where the platform itself gets wet, for example in a chiller wash-down or a fish and produce area. Stainless steel platforms and indicators belong in food areas.

The IP rating applies to the platform and the indicator separately. A sealed platform with an unsealed indicator fails at the indicator. Check both before buying.

Pallet scale or floor scale?

A floor scale, also called a platform scale, is a fixed low platform you bring the pallet to. Pallet scales as a group also cover weigh beams, U-frame scales and weigh-scale pallet trucks that go to the pallet.

• Platform or floor scale: the most stable and accurate, highest capacity, needs a ramp or pit mounting for pallet truck access. Wins when pallets pass one fixed point, such as goods-in or despatch.
• Weigh beams: two portable beams laid under the pallet at an adjustable spacing, wired to one indicator, stored away when not needed. Wins for odd-shaped loads and occasional use.
• U-frame scale: two beams joined in a U so a pump truck drives straight in. Wins where floor space is tight.
• Pallet truck scales: lift and weigh in one move. Convenient, but the load sits on a moving frame so readings vary more than on a fixed platform.

How to weigh a pallet

A UK standard pallet is 1200 x 1000 mm and a Euro pallet is 1200 x 800 mm. Roll the pallet onto the platform with a hand pallet truck via a ramp, lower it, back the truck off and read the indicator. Subtract the pallet weight if you need the net figure. A fixed platform on level concrete gives the most repeatable result.

London Pallet Trucks supplies the platform type only. Weigh beams, U-frames and pallet truck scales are described here for comparison and are not part of our range.

Printing weight tickets and connecting to your system

Many industrial indicators can drive a ticket or label printer, or send the weight to a PC over RS232 or USB. A printed ticket on every inbound pallet ends arguments with suppliers, and a label at despatch saves keying weights into your carrier portal.

Printer and data output options vary by indicator. Tell us on WhatsApp whether you need a printer, a data cable or a remote display and we will confirm what the indicator on your model supports before you order.

Most industrial indicators run on mains with a rechargeable battery for use away from a socket. We confirm the power arrangement for each model in the quote.

Trade approved or check-weighing: how to choose

Choose trade approved when the reading sets a price. Choose check-weighing for everything else. The approved version costs more because each unit is verified and marked, and it must be re-verified after metrological repair. That is wasted money on a goods-in scale that never touches an invoice.

The comparison table on this page sets the two side by side. Our launch range is the check-weighing type. The best trade approved scales for a counter are the ones whose e, platform size and capacity fit the goods you sell; we quote approved models on request.

Buying checklist

1. Capacity above your heaviest load including the pallet, bin or crate. A bigger capacity means a coarser division, so do not oversize.
2. Approved or check-weighing: will the reading ever appear on an invoice?
3. e or d: the division you need to see, and whether it must have legal standing.
4. Platform size in mm: large enough for the pallet, crate or trolley you weigh.
5. Platform height and ramp: low profile with a ramp for pallet truck loading, or pit mounted for a flush floor.
6. Material: mild steel painted for dry warehouses, stainless steel for food and wet areas.
7. IP rating on both the platform and the indicator.
8. Battery and mains: where will the scale sit and is there a socket?
9. Output: printer, RS232 or USB if you need tickets or data.
10. Indicator mounting: on the platform, on a column, or on the wall.
11. Minimum order for the scales range. Minimum order applies. Mix models in the range to reach it.
12. Lead time and delivery: see delivery and allow for it in your plan.

How to order and delivery

Made to order at our factory partners and delivered to your door by pallet carrier. Typical lead time 8 to 12 weeks from order confirmation. Deposit 30% on order, balance before despatch.

Every scale is new and made to order. Send the capacity, the job and your postcode on WhatsApp or email sales@londonpallettrucks.co.uk and you will get a trade price ex VAT, a lead time and a delivery charge in writing before you pay anything. Minimum order applies. Mix models in the range to reach it. Any mix of scale models counts towards the scales range minimum. See minimum order and apply for a trade credit account if you are a UK limited company or LLP.

We do not hire. We do not sell used. We sell to business customers only.

Sources

• The Non-automatic Weighing Instruments Regulations 2016, SI 2016/1152, legislation.gov.uk
• Weights and Measures Act 1985, legislation.gov.uk
• Product Safety and Metrology etc. (Amendment) Regulations 2024, legislation.gov.uk
• Business Companion: weighing equipment for use for trade, businesscompanion.info

This guide is general information, not legal advice. Check with your local Trading Standards service if you are unsure whether a particular use needs an approved scale.