5×5 risk matrix calculator
Pick how likely harm is and how bad it would be. The matrix gives the risk rating, from low to extreme, and what to do about it. Whatever the rating, the law asks you to eliminate the risk if you reasonably can, and to minimise it if you can't.
Rate a risk
The 5×5 risk matrix
| Likelihood ↓ / Consequence → | 1Insignificant | 2Minor | 3Moderate | 4Major | 5Catastrophic |
|---|---|---|---|---|---|
| 5Almost certain | Medium (5) | High (10) | High (15) | Extreme (20) | Extreme (25) |
| 4Likely | Medium (4) | Medium (8) | High (12) | Extreme (16) | Extreme (20) |
| 3Possible | Low (3) | Medium (6) | High (9) | High (12) | Extreme (15) |
| 2Unlikely | Low (2) | Low (4) | Medium (6) | High (8) | High (10) |
| 1Rare | Low (1) | Low (2) | Medium (3) | Medium (4) | High (5) |
- 5. Almost certain
- Expected to happen, or happens often
- 4. Likely
- Will probably happen at some time
- 3. Possible
- Might happen at some time
- 2. Unlikely
- Could happen, but isn't expected to
- 1. Rare
- Could happen only in exceptional circumstances
- 1. Insignificant
- No injury or illness
- 2. Minor
- First aid treatment
- 3. Moderate
- Medical treatment or time off work
- 4. Major
- Serious injury or illness, such as a hospital stay
- 5. Catastrophic
- Death or permanent disability
What each rating means
- Extreme
- Don't start, or stop work. Eliminate the hazard, or reduce the risk with higher-order controls, before anyone does the job.
- High
- Act before work starts: use higher-order controls, record them in the SWMS or risk assessment, and have a supervisor check them on site.
- Medium
- Put controls in place before work starts, name who's responsible for each, and check they're working.
- Low
- Manage it with your usual procedures and controls, and review it if the work changes.
How to use it
- Rate the risk as it is now, with the controls already in place, to decide what to deal with first.
- Choose controls from the top of the hierarchy: eliminate the hazard; if you can't, substitute it, isolate it or use engineering controls, then administrative controls, then PPE. Regulation 36
- Rate it again with the new controls, and record both in your risk assessment or SWMS.
- Review it when the work, the site or the crew changes, and after an incident.
The WHS laws don't require a risk matrix. They require you to eliminate risks so far as is reasonably practicable and, where you can't, to minimise them, following the hierarchy of control. A matrix is one way to decide which risks to deal with first. If your organisation has its own matrix, use that. WHS Act, section 17 · regulation 35 · regulation 36
Risk assessment templates
Record the hazard, the rating, the controls and who's responsible.
For high-risk construction work, you need a SWMS: browse SWMS templates · Hazards