How Is the CE Marking Used?

Earning the right to carry the CE marking is only part of the process; how, where, at what size and with what additional information the marking is applied to the product is governed by its own set of rules, which must be followed just as carefully. In practice, many companies complete their technical file and testing in full, yet still run into trouble during inspections because of small mistakes in the physical application of the marking. In this article we cover concrete, practice-oriented rules for correctly using the CE marking on a product. If you're wondering what the marking itself means and its legal status, see our article What Is the CE Marking?; here, rather than repeating that concept, we focus directly on the application rules.

Correct Use of the CE Marking on a Product

The rules for using the CE marking are based primarily on the visual template described in the annex to Regulation (EC) No 765/2008 and the affixing provisions found in the relevant product directives. These rules can be grouped into three main areas: preserving the visual integrity of the marking, correctly choosing where it is affixed, and correctly adding additional information (such as a notified body number) where required.

Size and Proportion Rules

The CE marking can be enlarged or reduced as long as the height-to-width ratio of the letters and the curve structure remain fixed. However, the vertical height must not go below a minimum of 5 millimeters, except in narrow exceptions dictated by the product's own nature. This minimum size is set to guarantee that the marking can be clearly read with the naked eye. A common mistake in practice is "compressing" the marking's proportions due to limited space on the product; this violates the marking's visual integrity and can be flagged as a non-conformity during inspections.

To scale the marking without distorting its proportions, it is recommended to use the reference template provided in the legislation (usually defined on a grid system). Ready-made vector templates containing the CE marking should be produced faithfully to this grid structure; manually redrawing the marking in a free drawing program can lead to proportion errors.

Choosing the Position: Where Should the Marking Be Affixed?

The general rule is that the CE marking should be affixed directly to the product itself. This can take the form of permanent printing, embossing, engraving or a durable label on the product body. If the product's size, shape or structure (for example, very small electronic components) makes affixing the marking directly to the product physically impossible or meaningless, the marking can be placed on the packaging and/or the documents provided with the product (user manual, warranty card, etc.). However, this exception applies only where it is genuinely technically impossible — affixing the marking only to the box instead of the product simply because it is more convenient is not acceptable.

The surface on which the marking is positioned should be chosen so that it does not lose visibility under the product's normal use conditions (cleaning, wear, heat, moisture). It is not recommended to place the marking on surfaces that wear, rub or are frequently replaced (such as removable covers), since this could cause the marking to disappear over the product's service life.

Permanence and Legibility

The legislation explicitly requires the CE marking to be "visible, legible and indelible." These three criteria are assessed independently: visibility means the marking is in a position that is easily noticeable during normal use of the product; legibility means the letters are printed clearly, without causing confusion; and indelibility means the marking remains permanent throughout the product's expected service life. Easily removable adhesive labels may not meet this permanence requirement, especially on products intended for outdoor use or frequent cleaning; for such products, methods like engraving, laser marking or permanent printing should be preferred.

Adding the Notified Body Number

For modules where a notified body is involved in the product's conformity assessment (for example, an audit of the production quality assurance system), the relevant body's four-digit identification number must be added immediately next to the CE marking, with no space between them. This number shows which independent body was involved in the process and is important for enabling traceability by audit authorities. For products proceeding under the self-declaration model, no such number is added — the CE marking alone is sufficient. See our article What Is a Notified Body? to learn which product groups require notified body involvement.

The Single-Marking Rule for Multiple Directives

If a product falls under more than one directive or regulation at the same time (for example, equipment subject to both the Machinery Directive and the Radio Equipment Directive), only a single CE marking appears on the product. This single marking expresses conformity with all applicable legislation at once. Having the manufacturer print a separate CE marking for each directive is both unnecessary and can create visual clutter that leads to confusion during inspections. What matters is that the technical file and declaration of conformity clearly specify which directives are covered — the marking itself remains singular.

Integrating the Marking into Manufacturing and Quality Control Processes

Correct use of the CE marking is not a one-off design decision — every company moving into mass production needs to integrate it into its own quality control system. The recommended approach in practice is to approve the mold, pad-printing plate or laser-engraving template that will apply the marking by comparing it against the reference vector file before production begins. This approval step prevents a single mistake made at the start of mass production from being repeated across thousands of units. It is also advisable to include the marking's size, position and legibility in the periodic quality-control sampling checklist, alongside other critical dimensional tolerances.

Particularly for companies that manufacture through contract manufacturing or third-party production, the responsibility for correctly applying the CE marking should not be fully delegated to the supplier. Since the brand owner is ultimately the party responsible for the product's CE marking, it should explicitly include the marking's technical specification (size, position, material, durability test results) in manufacturing contracts, and keep the pre-production sample approval process under its own control. This is a critical safeguard both during audits and in the event of a possible product recall.

The Marking's Relationship to Digital and Printed Documents

While the physical presence of the CE marking on the product or packaging remains the core requirement, many manufacturers today also choose to make the marking visible through digital channels (product web pages, e-commerce listings, digital user manuals). Although not mandated by the legislation, this is good practice that builds consumer trust. However, it is important to note that this digital visibility never replaces the mandatory physical marking on the product; the presence of a CE reference on an e-commerce page does not mean the product itself is correctly physically marked, and this distinction is made clear during inspections.

Relevant Directives and Standards

The CE marking's visual template and general affixing rules are defined in Regulation (EC) No 765/2008. However, some product directives also contain their own specific affixing provisions. For example, the Machinery Directive 2006/42/EC recommends placing the CE marking on the machine's rating plate, in the same area as the manufacturer's name and serial number — an approach largely preserved under the new Machinery Regulation (EU) 2023/1230. For electrical products under the Low Voltage Directive 2014/35/EU, the marking is usually found on the information label on the back or bottom surface of the device. For wireless devices under the Radio Equipment Directive 2014/53/EU, additional information showing which countries the device can be used in is also expected to be present in the technical documentation, alongside the CE marking. See our guide Which Directives Apply to My Product? to correctly determine the applicable combination of directives.

Step by Step

1. Determine which directives and regulations apply to your product and check for any special affixing provisions.
2. Complete the conformity assessment (testing, risk analysis, technical file).
3. Clarify whether self-declaration is sufficient or notified body involvement is required.
4. Choose the most appropriate surface to affix the marking to, based on visibility, permanence and durability criteria.
5. Use the reference template to determine the correct size without distorting the marking's proportions.
6. Add the notified body's identification number immediately next to the marking, if required.
7. Verify the marking's legibility and durability (wear, heat, moisture testing) on a pre-production sample.
8. Approve the marking's inclusion in mass production once the EU Declaration of Conformity is signed.
9. After the product is placed on the market, ensure the marking is regularly checked as part of quality control.

Most Common Mistakes

• Using the marking below the minimum height limit.
• Distorting letter proportions by compressing or stretching the marking.
• Printing only on the packaging when affixing it directly to the product is possible.
• Failing to meet the permanence requirement by using easily worn or removable labels.
• Unnecessarily adding a notified body number to a self-declared product, or the reverse — not adding it when required.
• Trying to print separate CE markings for multiple directives on the same product.
• Including the marking in mass production before the conformity assessment and EU Declaration of Conformity are complete.

Frequently Asked Questions

Planning Marking Placement Early in New Product Development

It is advisable for decisions about applying the CE marking to be made as early as possible in the product development process. Industrial design teams should plan, while finalizing the product's mold or shell design, exactly where the CE marking will be affixed, how much minimum space is needed, and how that space will be achieved in the manufacturing process (injection molding, casting, sheet-metal forming). If this planning is delayed, later stages of the design can run into problems such as not having enough room for the marking, having to compress its proportions, or being forced to push the marking into an inconspicuous, unsuitable location. Early planning both simplifies legislative compliance and prevents costly design revisions later in the manufacturing process.

Conclusion

Correct use of the CE marking deserves just as much attention as the technical file and declaration of conformity. Size, proportion, position, permanence and, where relevant, the notified body number are all concrete criteria checked during inspections. Failing to follow these rules can render a product non-conforming, no matter how solid the rest of the process is. This is why the physical application of the marking is the final and critical step of the CE process — one that should never be neglected.