Risk Assessment Calculator
What is a Hazard Rating Number (HNR)?
The Hazard Rating Number (HNR) is a quick, structured method for ranking the risks of a machine before it is placed on the market. It is a common input to the risk assessments required by the EU Machinery Directive 2006/42/EC: although the directive does not prescribe a scoring system, a numeric rating makes it easier to compare hazards, prioritise risk reduction measures, and document the logic of the safety file for CE marking.
How the HNR Formula Works
The rating is the product of four factors: HNR = LO × FE × DPH × NP. LO scores the likelihood of occurrence, FE how often people are exposed, DPH the degree of possible harm from a scratch up to a fatality, and NP the number of persons who can be exposed. Because the factors multiply, a machine that is rarely entered but can kill a whole crew produces a far higher score than one that is touched daily but can only pinch a finger — which reflects real risk tolerability better than a simple sum.
Interpreting the Result
The calculator classifies the product into four bands. A result up to 5 is considered negligible, up to 50 is still low but significant, up to 500 is high, and anything above 500 is unacceptable. High and unacceptable ratings show that risk reduction measures — guards, safety functions, safe stopping distances, interlocks, or a documented residual risk — must be planned and verified before the machine is CE marked.
Frequently Asked Questions
What does the Risk Assessment Calculator do?
It helps evaluate machinery risk levels per EU Machinery Directive 2006/42/EC by scoring severity, exposure, and avoidability to determine risk priority.
How do I use it?
Select hazard severity, exposure frequency, and avoidability. The tool calculates a risk score and shows the required risk reduction level.
Is it free?
Yes. This Kod5 tool runs in the browser, requires no installation, and is free to use.