Rate a hazard with the 5×5 risk matrix
A 5×5 risk matrix rates a hazard on two scales, how likely it is to cause harm and how bad that harm could be, and combines them into one rating. Use the matrix below to rate a risk, then download the template to record it.
Try the matrix
Download: Excel template (with scoring formulas) | Word template | PDF
How to use a 5×5 risk matrix
- Identify the hazard. Walk the job, talk to the workers doing it, and check incident records.
- Rate likelihood (1 to 5) with the controls you already have in place.
- Rate consequence (1 to 5) using the most likely serious outcome, not the worst you can imagine.
- Multiply the two to get a score from 1 to 25 and read off the rating.
- Add controls working down the hierarchy of controls, then rate the risk again (the residual risk).
- Record and review it. Put it in your risk register with an owner and a review date.
What the law asks for
No Australian WHS law requires a risk matrix. Under the model WHS Act a person conducting a business or undertaking (PCBU) must eliminate risks so far as is reasonably practicable and, if that isn’t reasonably practicable, minimise them so far as is reasonably practicable (s 17). The model WHS Regulations set out how: identify hazards (r 34), then eliminate or minimise risks using the hierarchy of control measures (r 35 and r 36), make sure controls stay effective (r 37), and review them in set situations, such as when a control isn’t working (for example, a notifiable incident happens because of the risk), before a change at the workplace, or when a health and safety representative asks (r 38).
Safe Work Australia’s model Code of Practice How to manage work health and safety risks describes a four-step process: identify hazards, assess risks, control risks and review controls. A matrix is one way to do the “assess” step. It helps you rank risks and decide what to deal with first. A low rating still leaves you with the job of controlling the risk.
Common mistakes
- Rating likelihood before you’ve written down which controls are already in place.
- Letting a low score justify skipping a control that is reasonably practicable. The SFAIRP duty still applies.
- Using different descriptors across teams, so scores can’t be compared. Agree one set and write it down.
- Rating once and filing it. Risks change when the work, the people or the site change.
Working in Victoria? The Occupational Health and Safety Act 2004 applies there instead of the model WHS Act, and it sets its own duty to eliminate or reduce risks so far as is reasonably practicable. The matrix works the same way under either law.
Keep every risk rating in one register
Lahebo’s risk register keeps your ratings, controls, owners and review dates together, with action tracking so someone owns the follow-up.
Frequently asked questions
What is a 5×5 risk matrix?
It’s a grid with five likelihood levels and five consequence levels. Multiplying the two gives a score from 1 to 25, which maps to a rating such as low, medium, high or extreme.
Does WHS law say I have to use a risk matrix?
No. The model WHS Regulations (r 34 to r 38) require you to identify hazards, control risks using the hierarchy of controls, and review those controls. A matrix is one common tool for ranking risks.
Should I use a 3×3, 4×4 or 5×5 matrix?
A 5×5 matrix gives more room to separate risks than a 3×3. What matters most is that everyone in your organisation uses the same descriptors and rating bands.
Sources
- Model Work Health and Safety Act, s 17 (management of risks)
- Model WHS Regulations, Part 3.1, r 32 to r 38
- Safe Work Australia, model Code of Practice: How to manage work health and safety risks
