Risk Assessment Matrix and 5x5 Scoring (UK)

A risk assessment matrix turns a judgement about risk into a simple number, so you can compare risks and show which need the most attention. The five by five matrix is the version almost every UK assessment uses. Here is how it works and how to read it.

What the matrix does

The matrix scores each risk on two scales, how likely harm is and how severe it would be, and multiplies them to give a risk rating. It does not replace your judgement, it records it in a way that is consistent and easy to compare across a job.

The 5x5 scoring

Likelihood runs from 1, very unlikely, to 5, almost certain. Severity runs from 1, minor first aid, to 5, fatal or life changing. Multiply the two and you get a score from 1 to 25. A low score such as 1 to 6 is usually acceptable with existing controls, a middle score 8 to 12 needs further action, and a high score 15 to 25 means the work should not proceed until the risk is reduced.

Before and after controls

Good practice is to score the risk twice, once as it would be with no controls and again with your controls in place. The drop between the two numbers shows the value of your controls and proves you have reduced the risk so far as is reasonably practicable.

Keep it honest

The matrix is only as good as the judgement behind it. Do not score everything low to make the form look tidy. The point is to surface the risks that genuinely need action.

Use a template with the matrix built in

Our risk assessment template has the five by five matrix and before and after scoring columns ready to use, with example rows. For how to fill it in field by field, see our guide to completing a risk assessment form.