A Guide to Trade Approvals:
Trade Approved Scales: What You Need to Know
Weighing scales are used across a wide range of industries for various applications. However, for certain uses, standard weighing scales are not suitable — trade approved scales are legally required. In this guide, we explain the importance of using trade approved scales, when they are required, and how to identify them.
What is a Trade Approved Scale?
A trade approved scale is any weighing scale that is legally certified for weighing goods priced by weight. These scales undergo rigorous testing to ensure they meet strict accuracy and construction standards, protecting both the seller and buyer. For example, a kitchen scale for personal use does not need to be trade approved, but a scale used in a sweet shop must be.
Industries requiring trade approved scales include:
- Industrial and commercial scales
- Jewellery weighing
- Professional food preparation
- Retail and point-of-sale weighing
Do I Need a Trade Approved Scale?
In the UK, it is a legal requirement to use trade approved scales when selling products priced by weight. This applies to:
- Sweet shops, fruit & veg stores, and any retail outlet selling by weight
- Foodstuffs (Legal-for-trade food scales)
- Soaps and personal care products
- Meat and fish (Butchers' scales)
- Bottled goods (e.g., alcohol)
- Fuels and energy products
- Precious metals, jewellery
- Animal feeds
- Pre-packaged items specifying weight
According to the NAWI Directive 2014/31/EU, trade approved scales are mandatory for:
- Commercial transactions based on weight
- Calculating tolls, tariffs, taxes, and penalties
- Legal regulations and court opinions
- Direct sales pricing and pre-packaging
- Medical monitoring and treatment
- Pharmaceutical preparation and laboratory analysis
Note: Trade approval is not needed when weighing ingredients for internal production processes unless the final product is sold by weight.
What is the Law on Using Trade Approved Scales?
The Weights and Measures Act 1985 requires trade approved scales for selling by weight. Trading Standards Officers may inspect businesses without notice to ensure compliance.
Penalties for non-compliance:
- 28-day notice to rectify non-compliance
- Fines exceeding £1,000
- Potential imprisonment for serious violations
It is also illegal to tamper with approved scales or to continue using inaccurate or unapproved equipment.
Who Can Certify a Trade Approved Scale?
Only a recognised Weights and Measures inspector or an officially approved body can certify a scale. Certification checks include accuracy, design, and resistance to interference. Approved scales receive a Declaration of Conformity.
Check if a certifying company is legitimate via the UKAS website.
How to Identify a Trade Approved Scale
You can verify a scale's trade approval status by:
- Checking product descriptions, packaging, or manuals for terms like: Class III approved, Legal for trade, Verified, EC stamped, or Stamped scales.
- Inspecting the dataplate underneath the scale for:
- CE mark (European Conformity)
- M mark (often with year, e.g., M21)
- Class II or Class III designation
- Older scales may also feature a crown stamp
Different Classes of Trade Approved Scale
Trade approved scales are classified by accuracy level:
- Class I & II: High precision (e.g., gold, gemstones, pharmaceuticals)
- Class III: General weighing (e.g., retail, industrial, commercial applications; readability 0.1g to 2g)
Using a scale with the correct class is critical to ensure legal compliance and measurement accuracy.