Technique

Cross-cut versus strip-cut: why particle size determines everything

3 May 2026 · 7 min read · DeSnipperaar

Everyone knows the image: a sheet of paper disappears into the shredder and comes out as strips. But the difference between those strips and the almost dusty confetti that emerges from an industrial shredder is enormous, and it is precisely that difference which determines whether your document is truly destroyed. Particle size is not a detail, it is the core of what makes paper destruction a security measure.

Strip-cut: long ribbons

The cheapest office shredders cut paper into long ribbons, often around 6 mm wide and the full length of the sheet. It looks convincing; all the text is cut through. But reconstruction of strip-cut is surprisingly simple: lay the strips in order, and you can read the lines again even without specialised software. In a quiet afternoon someone with tweezers can reconstruct an A4.

• DIN 66399: P-1 (max 2,000 mm²) or P-2 (max 800 mm²).
• Suitable for: non-confidential household paper. Promotional material without customer data. Advertising leaflets.
• Not suitable for: virtually all business documents with personal data, turnover figures or contractual content.

Cross-cut: confetti

A cross-cut shredder cuts paper both horizontally and vertically into small pieces. A typical business cross-cut produces particles of around 4×30 mm. Reconstruction becomes orders of magnitude harder; hundreds of pieces per page, no sequence, and with a box full of mixed documents practically impossible.

• DIN 66399: P-3 (max 320 mm²) or P-4 (max 160 mm²).
• Suitable for: customer administration, financial documents, HR records without special category data.
• Not suitable for: medical files, lawyers' files, data covered by professional confidentiality.

Micro-cut: dust

A micro-cut shredder produces particles a few millimetres in length and width. What emerges resembles ground grain more than paper shred. Reconstruction is in fact impossible: even a specialised lab faces an intractable combinatorial problem.

• DIN 66399: P-5 (max 30 mm²) or P-6 (max 10 mm²).
• Suitable for: special category personal data, medical files, legal files, financially confidential data.
• P-7 (max 5 mm²): defence and intelligence level.

The relevance of particle size lies not in feeling but in measuring. A solid average of 30 mm² means that some pieces are larger and smaller, but that the vast majority fall within P-5.

What does the DARPA challenge say about this?

In 2011 DARPA offered a 50,000 dollar prize to anyone who could reconstruct shredded documents. Five strip-cut documents and simple cross-cut were solved within weeks by teams that combined computer vision with manual sorting. Documents at P-5 level proved practically uncrackable within a reasonable time. The scientific conclusion was unambiguous: particle size is not marketing, it is a mathematical threshold.

Which level do you need?

For most Dutch organisations P-4 is sufficient. If you work with customer administration, turnover data or contract administration without a medical component, that suffices. If you work with:

• medical files (WGBO);
• lawyers' or notaries' files (confidentiality);
• financial client data of private individuals;
• copies of identity documents (BSN);

then choose P-5. Our on-site shredders run on P-5 as standard because we get it right in one go for most of our business clients. Whether you then choose on-site or offsite is a separate consideration.

Common error: length versus width

The DIN standard measures the area of the particle, not the width alone. A shred 1 mm wide and 100 mm long has an area of 100 mm², so that is P-3, not P-5. Some providers advertise ‘1 mm fine’ as a qualification for their shredder, while the device actually produces long thin strips that come out at P-3 or P-4. Always ask for the area classification or a measurement in mm², not for the width.

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Unsure which level your archive needs? Ask your question via desnipperaar.nl, or read our article on the Certificate of Destruction for what belongs on it.