Paper Shredder Security Levels Explained
Paper shredder security levels explained
Shredders are sold by security level — P-1 through P-7 under the DIN 66399 standard — and the numbers are not marketing. Each level sets a maximum particle size. Buying a level higher than you need costs real money and slows the machine down; buying lower than you need can put you offside with the Privacy Act.
The short answer. Most Australian offices should be on P-4: it is the standard for sensitive confidential data and covers customer records, HR files and financial paperwork. Step to P-5 or above only for genuinely classified material. P-3 and below is fine for internal admin that isn't personal information.
The levels, side by side
| Level | Cut type | Max particle size | What it's for |
|---|---|---|---|
| P-1 | Strip cut | < 2,000 mm² (strips < 12mm wide) | Very low security — general internal documents only |
| P-2 | Strip cut | < 800 mm² (strips < 6mm wide) | Low security — general office paperwork |
| P-3 | Cross cut | < 320 mm² (< 2mm wide) | Medium — confidential documents |
| P-4 | Cross cut / micro cut | < 160 mm² (< 6mm wide) | Medium-high — sensitive confidential data. The office default. |
| P-5 | Micro cut | < 30 mm² (< 2mm wide) | High — highly confidential material |
| P-6 | Micro cut | < 10 mm² (< 1mm wide) | Very high — secret / classified |
| P-7 | Micro cut | < 5 mm² (< 1mm wide) | Extremely high — maximum confidentiality |
Note the pattern: the jump that matters most is P-3 to P-4, where particle area halves. From P-5 upward the security gain per dollar drops sharply, throughput falls, bins fill faster, and the output becomes harder to recycle.
The Privacy Act angle
Australian Privacy Principle 11.2 requires an organisation to take reasonable steps to destroy or de-identify personal information once it is no longer needed for a permitted purpose. On paper records the regulator is direct about what does not count:
“Disposal through garbage or recycling collection would not ordinarily constitute taking reasonable steps to destroy the personal information, unless the personal information had already been destroyed through a process such as pulping, burning, pulverising, disintegrating or shredding.”
— Office of the Australian Information Commissioner, APP Guidelines Chapter 11In practice: a recycling bin is not destruction. If your business holds customer, patient, tenant or employee records on paper, shredding them is the step that makes disposal defensible.
Choosing by volume, not just level
Security level tells you how finely it cuts. Three other specs decide whether the machine survives:
- Sheet capacity — how many sheets per pass. Buy above your habit: feeding 12 sheets into a 10-sheet machine is the usual cause of jams.
- Run time — personal shredders run for a few minutes then need to cool. A departmental machine runs continuously. If more than one person feeds it, you want continuous duty.
- Bin size — higher security levels produce more particles from the same page, so a P-5 bin fills noticeably faster than a P-4 one.
Also check whether the machine takes staples, paper clips, credit cards and CDs. Most modern office units handle staples; not all handle cards.
Keeping it alive
Cross cut and micro cut heads need oiling — the single most common cause of a dead shredder is an unoiled cutting head, not a jam. Oil the head across a sheet of paper roughly every time you empty the bin, and use shredder oil rather than a general lubricant, which can gum the mechanism. Matched waste bags are worth it too: a bag that fits means the bin gets emptied instead of overfilled.
Sources: security levels and particle sizes per the DIN 66399 standard for the destruction of data carriers. Privacy quotation from the Australian Privacy Principles Guidelines, Chapter 11 — APP 11 Security of personal information, Office of the Australian Information Commissioner (oaic.gov.au). General information for buying purposes only, not legal advice — obligations depend on your organisation's circumstances.
Not sure which level applies to you?
Tell us what's being destroyed — customer records, patient files, tender documents, general admin — and how much per week, and we'll match a machine to it.
