Paper Shredder Security Levels Explained (DIN 66399, P-1 to P-7)

What Is the DIN 66399 Standard?

DIN 66399 is a German standard that defines how finely a document needs to be shredded based on how sensitive it is. It sets out 7 levels (P-1 through P-7) — the higher the level, the smaller the resulting particles, and the higher the security.

The Security Levels, P-1 to P-7

- P-1 — strip-cut, particles up to 2,000mm² — general, non-sensitive documents
- P-2 — strip-cut, up to 800mm² — basic internal use
- P-3 — cross-cut, up to 320mm² — medium security, suitable for most offices
- P-4 — fine cross-cut, up to 160mm² — confidential documents
- P-5 — micro-cut, up to 30mm² — highly sensitive data
- P-6 — micro-cut, up to 10mm² — very high security
- P-7 — micro-cut, up to 5mm² — maximum security, classified material

How to Choose the Right Level

- General office paper, drafts — P-2/P-3
- Invoices, contracts, employee records — P-4
- Financial, medical, or legal confidential documents — P-5
- Government or classified material — P-6/P-7

Research generally points to P-3 as the sweet spot for most offices — a solid balance between security, cost, and how well the shredded paper can still be recycled.

Frequently Asked Questions

What level is right for a typical office?
P-3 or P-4 covers most office needs.

Can a shredded document be reconstructed?
At the lowest levels (P-1, P-2) it's theoretically possible; above P-5 it becomes practically impossible.

Why are higher-security shredders more expensive?
Finer cutting requires a more complex mechanism, which runs slower and needs more frequent maintenance.

We carry shredders across every security level — see our range for the one that fits your office.