DIN 66399 Paper Shredder Security Levels

Which security level do you need for paper shredding?

When you are looking for a new shredder for home or at the office, you often see the security level of a paper shredder. For instance, P-2, P-3, or P-4. What does the security level mean, and why is it important to pay attention to it when buying a new shredder machine? On this page, we explain the shredder security levels.

Brief: The sweet spot for shredding documents is security level P-3. This offers enough data security for most documents, it is cost-efficient, it is time-efficient and it is more sustainable since the shredder output can be recycled better.

Compare the different security levels

What is DIN 66399?

When you look at a paper shredder’s specifications, you often see the security level with a DIN classification next to it. For example, P-1 or P-3. But what does it mean?

The DIN P-level is part of the official German DIN 66399 standard (since 2012), the international standard for secure shredding of data media developed by the Deutsches Institut für Normung (DIN), which translates to the German Institute for Standardization.

This DIN-norm contains destruction requirements for multiple media categories. Namely paper, film, optical media, magnetic data media, hard drives and electronic data media.

DIN 66399 (before DIN 32757) classifies the security levels for six media categories. Such as hard drives (H), optical media (O), and paper-based products (P).

For paper, there are seven security levels. The levels range from P-1 to P-7. The higher the DIN level, the smaller the paper particles become after shredding a document.

The seven security levels are divided into three protection classes or categories. Some security levels overlap two protection classes:

Protection class 1

• Normal security for internal data
• Security level: DIN P-1, DIN P-2, DIN P-3
• Low level of security

Protection class 2

• High security for confidential data
• Security level: DIN P-3, DIN P-4, DIN P-5
• High level of security

Protection class 3

• Very high protection for confidential and secret data
• Security level: DIN P-4, DIN P-5, DIN P-6, DIN P-7
• Very high level of security

We recommend a paper shredder that sits in protection category 2 with a P-3, P-4, or P-5 security level for most shredding needs. These shredders suffice most requirements for secure shredding of confidential documents.

DIN P-x: The size of the particle

The security levels for paper shredders are part of the official DIN 66399 standard for paper destruction. This standard contains seven security levels for paper destruction, which indicates the minimal requirements for the paper particles’ size after shredding a document. The seven security levels are P-1, P-2, P-3, P-4, P-5, P-6, and P-7. The higher the number, the smaller the size of the particle gets.

Besides for paper, the P security level is also applicable for film and printing forms.

For instance, when you are looking for high security and want small particles, you are better off with a P-5 paper shredder than a P-2 paper shredder. That is because the paper particles from a P-5 micro-cut shredder are microscopic in comparison with the strips of a P-2 strip-cut shredder.

Want to visualize and compare the shred sizes? Our friends over at Intimus made a ‘Shred Size Visualizer’. This image shows you a clear comparison between the different DIN security levels.

Did you know that a level 6/ P-7 paper shredder destroys a standard A4 document (8,5″x 11″ sheet) into 12,053 pieces? Quite amazing.

Security levels infographic

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Particle size

Besides security levels, you can also find the cut type of paper shredders. All paper shredders are divided into three types of paper cuts. These are strip-cut, cross-cut, and micro-cut. Below you can see all the security levels from the German DIN 66399 standard for paper destruction:

1. Strip-cut – Low level of security
2. Cross-cut – Medium level of security
3. Micro-cut – High level of security

Cross-cut and micro-cut

There is some confusion about the difference between a cross-cut or micro-cut shredder. Officially a micro-cut shredder is classified as a P-5, P-6, or P-7 shredder.

But you will see that a lot of paper shredder manufacturers and stores classify a P-4 shredder as a micro-cut shredder as well. We see this for shredders that are offered in the US. Fellowes tells us that “the reason for this is that the term micro-cut is used on some P-4 Machines in the US, whereas in Europe it is only P-5.

Since it is very common that a P-4 shredder is called ‘micro-cut’ or ‘high security’, we also use this term for P-4 classified shredders.

A P-4 shredder offers more security than a P-3 shredder. Some P-4 shredders produce tiny paper particles after shredding a document, making the particles more ‘micro-cut’ than a P-3 cut. DIN 66399 states that a P-4 shredder should shred particles smaller than 320 mm² or 0.5 in².

Research shows that security level P-3 is optimal for most uses

Is a higher-level paper shredder always the best option? Research, performed by the Dutch certification body CA+, says it is not always the case. CA+ has conducted research into the most effective security level among various certified companies in 2021. The question they asked was: What is the best security level to use for shredding paper documents where confidentiality and sustainability are also guaranteed?

The chart above compares the cost of destructing paper per tonne, the recycling rate, and the rate of security in percentages. What stands out is security level P-3 as the optimum. It combines the best of both worlds: optimal recycling rates, relatively low costs, and high data security.

Confidentiality remains stable after P-3, which makes level P-3 an optimum for paper shredding.

A higher security level, and thus smaller paper particles (P-4 and higher), offers a slight increase in security percentage but a far higher decrease in recycling percentage and a big increase in costs.

What does the cost of paper shredding entail? Shredding documents at a higher security level requires more energy, more time, and more expensive shredding machinery. This goes for shredding companies, but also for paper shredder machines used at work or at home.

For a smaller shred size, the amount of energy required increases, and the costs also increase by 75%.

Why does the recycling rate decrease by a higher security level? The reason for this is that a smaller shred size is far more difficult to recycle. Firstly it is difficult to nearly impossible to filter the small-sized shreds at the recycling facility, this is especially applicable to single-stream recycling processes. Secondly, a smaller shred size destroys the source of paper, which are wood fibers. These fibers are getting shorter and shorter with a higher security level. For instance, security level P-7 is comparable with fine dust. This means that intensively destroyed paper can’t be recycled and thus is far less sustainable.

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Security Level DIN 66399: P-1
Strip-cut Paper Shredder

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Security Level DIN 66399: P-2
Strip-cut Paper Shredder

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Security Level DIN 66399: P-3
Cross-cut Paper Shredder

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Security Level DIN 66399: P-4
Cross-cut / Micro-cut Paper Shredder

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Security Level DIN 66399: P-5
Micro-cut Paper Shredder

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Security Level DIN 66399: P-6
Micro-cut Paper Shredder

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Security Level DIN 66399: P-7
Micro-cut Paper Shredder

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Paper shredder information and recommendations

Which paper shredder is the best shredder for you to buy? 

To destroy sensitive documents with personal information, medical information, financial information, or other confidential information, we recommend using a cross-cut shredder or a micro-cut shredder. Read more about these types of paper shredders here:

• Strip-cut paper shredders
• Cross-cut paper shredders
• Micro-cut paper shredders