The E Symbol on Food Packaging: Complete UK Guide to the E-Mark and Average Quantity System
If you have ever noticed a small lowercase “e” symbol next to the weight or volume on food packaging, you may have wondered what it means. The e-mark (officially written as the estimated sign) is not a brand logo or quality badge. It is a legal declaration by the packer that the contents of the package comply with the average quantity system, a framework governed by the Weights and Measures (Packaged Goods) Regulations 2006.
This guide explains everything UK food producers, manufacturers and importers need to know about the e-mark: what it means, the legal rules behind it, how the three packers rules work, the tolerable negative error (TNE) tolerances, and practical steps to achieve compliance. Whether you are a small bakery or a large-scale food manufacturer, understanding the e-symbol is essential for accurate food labelling.
Table of Contents
- What Is the E Symbol on Food Packaging?
- The E Symbol vs E Numbers: What Is the Difference?
- Legal Basis: UK Legislation Behind the E-Mark
- How the Average Quantity System Works
- The Three Packers Rules Explained
- Tolerable Negative Error (TNE): The Permitted Margins
- Who Can Use the E-Mark?
- How to Display the E Symbol on Your Labels
- Checking Compliance: Sampling and Record Keeping
- Enforcement and Penalties
- The E-Mark After Brexit
- Practical Steps to Achieve E-Mark Compliance
- Common Mistakes to Avoid
- Frequently Asked Questions
What Is the E Symbol on Food Packaging?
The e-mark is a small stylised lowercase “e” that appears next to the declared weight or volume on prepackaged goods. It stands for “estimated” and is a declaration by the packer or importer that the package has been filled in accordance with the average quantity system.
Critically, the e-mark does not mean the weight is merely a guess or approximation. It means the opposite: that the weight or volume has been measured using controlled processes and that the batch as a whole complies with strict legal tolerances. The average contents of the batch will not be less than the quantity stated on the label, and only a very small proportion of individual packages will fall below defined margins.
You will find the e-symbol on a wide range of prepackaged products including food, drinks, cosmetics and household goods. It applies to any product sold by weight or volume in quantities between 5g (or 5ml) and 25kg (or 25 litres).
The E Symbol vs E Numbers: What Is the Difference?
A common source of confusion is the difference between the e-mark and E numbers. They are entirely unrelated:
- The e-mark is a metrological symbol relating to quantity and weight accuracy. It appears next to the net weight or volume declaration on packaging.
- E numbers (such as E300, E621) are codes for approved food additives used across Europe. These appear in ingredients lists and have nothing to do with packaging weight.
If a customer asks about the “e” on your food label next to the weight, it is the estimated quantity mark. If they ask about the “E” followed by a number in the ingredients, that is a food additive code.
Legal Basis: UK Legislation Behind the E-Mark
The e-mark system in the UK is governed by several pieces of legislation:
- Weights and Measures Act 1985: The primary UK legislation governing trade measurement, providing the overarching legal framework for quantity control of packaged goods.
- Weights and Measures (Packaged Goods) Regulations 2006 (SI 2006/659): The specific regulations that set out the programme of quantity control, including the three packers rules, tolerable negative errors, and the conditions for using the e-mark.
- EU Directive 76/211/EEC (retained as assimilated law): The original European directive on prepackaged products, which introduced the e-mark system. This continues to apply in the UK as retained EU law post-Brexit.
- Regulation (EU) No 1169/2011 (Food Information to Consumers): Requires net quantity declarations on food labels, which is the quantity figure that the e-mark sits alongside. For more on this, see our nutrition declaration guide.
The key point for food businesses is this: using the e-mark is entirely voluntary. However, if you choose to use it, you must fully comply with all requirements of the Weights and Measures (Packaged Goods) Regulations 2006. You cannot simply add the symbol to your labels without implementing the necessary quantity control procedures.
How the Average Quantity System Works
The average quantity system recognises a practical reality of food production: it is virtually impossible to fill every single package to exactly the same weight or volume. Slight variations are inevitable in any packing process, whether you are filling bags of crisps, bottling sauces, or weighing portions of cheese.
Rather than requiring every individual package to contain at least the stated quantity (which would force packers to significantly overfill to avoid any package falling short), the average system allows for controlled variation. The principle is straightforward: across a batch of packages, the average contents must meet or exceed the declared quantity, and only a very small proportion of individual packages may fall below defined margins.
This system benefits both consumers and businesses. Consumers are protected from systematic underfilling, while businesses can operate their filling lines efficiently without excessive product giveaway. The alternative, known as the minimum quantity system, requires every single package to contain at least the stated amount, which typically results in significant overfill and higher costs.
What Products Does It Apply To?
The average quantity system applies to prepackaged goods that are:
- Made up without the customer being present
- Sold in pre-determined constant quantities by weight or volume
- Between 5g (or 5ml) and 25kg (or 25 litres) in nominal quantity
It does not apply to catchweight items (such as prepacked cheese where the price varies with individual weight), goods sold loose in the presence of the purchaser, or items sold by number rather than weight (such as a box of eggs).
The Three Packers Rules Explained
The cornerstone of the average quantity system is the “three packers rules”. Every batch of packages must satisfy all three of these rules simultaneously. Failing any one rule means the batch is non-compliant.
Rule 1: The Average Rule
The actual contents of the packages in a batch must not be less, on average, than the nominal quantity (the weight or volume stated on the label). This is the fundamental principle: across the batch, customers are getting what the label says they are getting.
Rule 2: The Tolerable Negative Error (TNE) Rule
The proportion of packages that fall below the nominal quantity by more than the tolerable negative error (TNE) must not exceed 2.5% of the batch. In other words, no more than 1 in 40 packages should be short by more than the permitted margin. The TNE values are set out in the table below and vary depending on the declared quantity.
Rule 3: The Double TNE Rule
No individual package may be short of the declared quantity by more than twice the TNE. This is an absolute limit. Even a single package falling below this threshold means the batch fails, regardless of how good the average is.
These three rules work together to create a fair system. Rule 1 protects the consumer from systematic underfilling. Rule 2 limits how many packages can be individually short. Rule 3 prevents any severely underfilled packages from reaching the market.
Tolerable Negative Error (TNE): The Permitted Margins
The tolerable negative error is the maximum amount by which an individual package can fall below the declared quantity before it counts as a “non-standard” package under Rule 2. The TNE varies based on the nominal quantity of the product:
| Nominal Quantity (g or ml) | Tolerable Negative Error (TNE) |
|---|---|
| 5 to 50 | 9% of nominal quantity |
| 50 to 100 | 4.5 g or ml |
| 100 to 200 | 4.5% of nominal quantity |
| 200 to 300 | 9 g or ml |
| 300 to 500 | 3% of nominal quantity |
| 500 to 1,000 | 15 g or ml |
| 1,000 to 10,000 | 1.5% of nominal quantity |
Practical TNE Examples
To illustrate how these tolerances work in practice:
- A 35g bag of crisps: The TNE is 9% of 35g = 3.15g. So the package must contain at least 31.85g to stay within the TNE (Rule 2). It must contain at least 28.70g to comply with the double TNE (Rule 3).
- A 500g jar of jam: The TNE is 15g. The package must contain at least 485g to be within the TNE. No package can contain less than 470g (double TNE).
- A 330ml can of soft drink: The TNE is 3% of 330ml = 9.9ml. The package must contain at least 320.1ml (TNE). No can may contain less than 310.2ml (double TNE).
- A 75g bar of chocolate: The TNE is 4.5g (fixed amount for 50-100g range). The bar must contain at least 70.5g. No bar may contain less than 66g.
- A 1 litre bottle of milk: The TNE is 1.5% of 1,000ml = 15ml. The bottle must contain at least 985ml. No bottle may contain less than 970ml.
Remember: these tolerances apply to individual packages. The batch average (Rule 1) must still meet or exceed the declared quantity.
Who Can Use the E-Mark?
Any packer or importer of prepackaged goods can use the e-mark, provided they meet all the requirements of the Weights and Measures (Packaged Goods) Regulations 2006. There is no registration, certification or approval process. You do not need to apply to Trading Standards or any other authority for permission.
However, using the e-mark carries legal obligations. By placing the symbol on your packaging, you are making a legal declaration that:
- Your packages comply with the three packers rules
- You carry out appropriate quantity checks using suitably accurate equipment
- You maintain records of your checks for at least 12 months
- The nominal quantity falls between 5g/ml and 10kg/L for e-marked packages (note: the average system itself covers up to 25kg/L, but the e-mark is limited to 10kg/L)
Using the e-mark when you do not comply with these requirements is a criminal offence. It is far better not to use the symbol than to use it incorrectly.
How to Display the E Symbol on Your Labels
If you decide to use the e-mark on your food labels, the regulations specify how it must appear:
- Position: The e-mark must be placed in the same field of vision as the nominal quantity declaration. It typically appears immediately after or alongside the weight or volume figure, for example: “500g e” or “330ml e”.
- Minimum size: The e-symbol must be at least 3mm in height.
- Legibility: The mark must be indelible, clearly legible and visible under normal conditions. It should not blend into the background or be easily worn off during handling.
- Quantity format: The declared quantity must be shown as a figure followed by the unit of measurement or its abbreviation (g, kg, ml, cl, or L). Metric units are mandatory.
When we design and print custom labels at PID Labelling, we ensure the e-mark is correctly positioned and sized as part of your label layout. If you are unsure about placement, our team can advise on the best approach for your packaging format.
Checking Compliance: Sampling and Record Keeping
If you use the e-mark (or simply follow the average quantity system), you must carry out regular checks on your packing process. The regulations require you to measure the quantity in each package within a sample using appropriately accurate equipment, or to operate a rigorous statistical sampling and testing system.
How Often to Check
The frequency of checks depends on your production speed:
- Lines producing fewer than 10,000 packs per hour: At least one sample check per hour
- Lines producing 10,000 or more packs per hour: At least one sample check per 10,000 packages
The maximum batch size for end-of-line checks is your hourly throughput. For example, if you produce 3,000 packages per hour, each batch for checking purposes should be no more than 3,000 packages.
What to Record
Your records must demonstrate compliance with all three packers rules. As a minimum, you should record:
- Product name and batch number
- Date and time of the check
- Number of packages in the batch
- Number of packages checked (sample size)
- Individual weights or volumes measured
- Results of the check (pass/fail against each rule)
- Any corrections or adjustments made to the filling process
These records must be kept for 12 months from the time the packages leave your possession, or until the end of the shelf life of the product, whichever comes first.
Equipment Requirements
Your weighing or measuring equipment must be suitable for the task and regularly calibrated. For most food businesses, this means using trade-approved scales that are tested and verified by an approved verifier. The accuracy of your equipment must be sufficient to detect whether packages fall outside the tolerable negative error.
Destructive vs Non-Destructive Testing
Where your packaging has a consistent, known weight (known as the tare weight), you can weigh the filled package and subtract the tare to determine the net contents. This is non-destructive testing, as you do not need to open the package.
If your packaging weight varies significantly, you may need to open packages to weigh the contents directly. This is destructive testing and is less efficient but sometimes necessary. To minimise the need for destructive testing, work with your packaging supplier to ensure consistent tare weights.
Enforcement and Penalties
Enforcement of the Weights and Measures (Packaged Goods) Regulations 2006 is carried out by local authority Trading Standards services. Trading Standards officers have the power to:
- Enter premises where packaged goods are produced, stored or sold
- Inspect and test packages from production lines or shop shelves
- Examine records and documentation
- Take samples for reference testing
Non-compliance can result in prosecution. Offences under the regulations carry penalties including fines. Using the e-mark on packages that do not comply with the three packers rules is itself an offence. Proceedings must be brought within 12 months of the offence being committed.
In practice, Trading Standards will often work with businesses to achieve compliance before resorting to prosecution, particularly for first-time issues. Many local authorities offer advice and support through Primary Authority partnerships, which can provide formal assured advice on compliance.
The E-Mark After Brexit
Since the UK left the European Union on 1 January 2021, the e-mark is no longer a requirement for selling goods within the UK market. However, the UK government has confirmed that the voluntary use of the e-mark continues to be recognised under UK law.
For UK businesses, this means:
- Selling in the UK only: Using the e-mark is voluntary but still perfectly valid. The underlying Weights and Measures (Packaged Goods) Regulations 2006 remain fully in force.
- Exporting to the EU: The e-mark is especially valuable if you export to EU countries. The mark is mutually recognised and demonstrates compliance with European packaging quantity standards, which can simplify market access and avoid additional checks.
- Importing from the EU: EU products bearing the e-mark continue to be accepted in the UK.
Even if you only sell within the UK, using the e-mark can serve as a mark of professionalism and quality assurance, signalling to retailers and consumers that your quantity control processes meet recognised standards.
Practical Steps to Achieve E-Mark Compliance
If you want to start using the e-mark on your food packaging, follow these steps:
Step 1: Assess Your Packing Process
Understand the variability in your filling process. How much does the quantity vary from package to package? Measure a sample of packages from your production line to determine the standard deviation of your fill weights. This will tell you how tightly your process performs and whether you can reliably meet all three packers rules.
Step 2: Set Your Target Fill Quantity
Based on your process variability, set a target fill quantity that is high enough to ensure all three rules are met. If your process is highly variable, you will need to set a higher target to ensure the average stays above the declared quantity and that very few packages fall below the TNE. Your local Trading Standards service can help you calculate appropriate target quantities.
Step 3: Invest in Accurate Equipment
Ensure your filling equipment is capable of achieving the necessary accuracy and that your checking equipment (scales) is suitable for the task and regularly calibrated. For most food applications, trade-approved scales are essential.
Step 4: Implement a Checking Regime
Establish a regular sampling and checking schedule based on your production throughput. Document your procedures clearly so that all staff involved in packing understand the requirements and know what to do if a check fails.
Step 5: Maintain Detailed Records
Keep thorough records of every check, including the results and any corrective actions taken. Store these for at least 12 months. Good record-keeping is not just a legal requirement; it is your defence in the event of a Trading Standards inspection.
Step 6: Update Your Labels
Once you are confident your processes comply, work with your label supplier to add the e-mark to your food labels. Ensure it is correctly positioned next to the quantity declaration, at least 3mm tall, and clearly legible. At PID Labelling, we can incorporate the e-mark into your label design as part of our custom label printing service.
Step 7: Seek Advice if Unsure
Contact your local Trading Standards service for specific guidance. Many authorities offer free advice to businesses, and some provide Primary Authority partnerships that give formal, assured compliance guidance.
Common Mistakes to Avoid
Based on common compliance issues, here are the mistakes to watch out for:
- Using the e-mark without compliance checks: Adding the symbol to your labels without implementing the necessary sampling and record-keeping procedures is an offence. The e-mark is a legal declaration, not a design element.
- Inconsistent tare weights: If your packaging varies significantly in weight, your net quantity calculations will be unreliable. Work with your packaging supplier to ensure consistency.
- Infrequent checks: Checking once a day on a high-speed line is not sufficient. Match your checking frequency to your throughput as required by the regulations.
- Ignoring process drift: Filling equipment can drift over time or between batches. Regular monitoring and adjustment is essential to maintain compliance.
- Poor record keeping: If you cannot produce records demonstrating compliance, you are effectively non-compliant. Trading Standards will expect to see documented evidence.
- Confusing average with minimum: The average system allows some packages to be below the declared quantity (within limits). But this is not a licence to systematically underfill. The batch average must always meet or exceed the stated amount.
- Forgetting desiccation: Some products lose moisture after packing. If you are checking at the point of sale rather than at the point of packing, natural moisture loss may cause apparent shortfalls. The regulations require you to demonstrate that any shortfall is due to desiccation after packing, not underfilling.
Frequently Asked Questions
Is the e-mark legally required in the UK?
No. The e-mark is entirely voluntary. There is no legal requirement to display it on your packaging. However, all packers must comply with the Weights and Measures Act 1985 regarding quantity accuracy, regardless of whether they use the e-mark. The e-mark is a specific declaration that you follow the average quantity system with its associated checking and record-keeping requirements.
What happens if I do not use the e-mark?
If you choose not to use the e-mark, you can either follow the average quantity system without displaying the symbol, or use the minimum quantity system where every individual package must contain at least the stated quantity. Many smaller food businesses operate perfectly well without the e-mark.
Does the e-mark apply to products sold by number?
No. The e-mark and the average quantity system only apply to products sold by weight or volume. Products sold by count (such as a box of teabags or a pack of biscuits counted individually) fall outside these regulations.
Can I use the e-mark on very small or very large packages?
The e-mark can only be used on packages with a nominal quantity between 5g (or 5ml) and 10kg (or 10 litres). The average system itself covers packages up to 25kg/25L, but the e-mark is restricted to the lower range.
What is the difference between the average system and the minimum system?
Under the average system, the batch average must meet the declared quantity, and a small proportion of individual packages may be slightly below (within the TNE). Under the minimum system, every individual package must contain at least the declared quantity. The minimum system has no tolerance for individual shortfalls but does not require the same statistical checking regime.
Do I need to tell Trading Standards I am using the e-mark?
No. There is no notification or registration requirement. You can start using the e-mark as soon as you are confident your processes comply. However, you must be able to demonstrate compliance if inspected.
What about products that lose weight after packing?
Some products, particularly fresh foods, lose moisture over time (desiccation). If your products are checked at the point of sale and found to be short, you can defend the shortfall if you can prove the packages were correctly filled at the time of packing and that any loss is due to natural desiccation. This requires good records of your fill weights at the point of packing.
Does the e-mark apply to non-food products?
Yes. The e-mark and the average quantity system apply to all prepackaged goods sold by weight or volume, including cosmetics, cleaning products, paints and other non-food items. The regulations are not limited to food.
Get Expert Help With Your Food Labels
Getting the e-mark right is just one element of compliant food labelling. At PID Labelling, we work with food businesses of all sizes to create accurate, professional labels that meet UK regulatory requirements. From bakery labels and sandwich labels to drinks labels and dairy labels, we understand the labelling requirements your products must meet.
Our labelling solutions include thermal printing systems for variable data like batch codes and date marks, and our Nutridata software to help you calculate nutrition information and manage allergen declarations.
Call us on 01332 864895 to discuss your labelling requirements, or fill in our contact form and we will get back to you.
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All food labelling guides are provided in good faith for information purposes only and do not constitute legal advice. For specific compliance questions about specific labelling laws, contact a specialist or contact your local Trading Standards authority. Read our Regulatory Information Disclaimer