Job Hazard Analysis Risk Score Calculator
Calculate the risk score for workplace hazards using the standard Job Hazard Analysis (JHA) methodology. The risk score combines the likelihood of an incident, its potential severity, and the frequency of exposure to determine overall risk level and recommended action priority.
Formula
Risk Score = Likelihood (L) × Severity (S) × Exposure (E)
- Likelihood (L): Probability that the hazardous event will occur, rated 1 (Improbable) to 5 (Frequent).
- Severity (S): Potential consequence or harm if the hazardous event occurs, rated 1 (Negligible) to 5 (Catastrophic).
- Exposure (E): Frequency with which personnel are exposed to the hazard, rated 1 (Rarely) to 5 (Continuously).
- Maximum Score: 5 × 5 × 5 = 125
- Risk Percentage: (Risk Score / 125) × 100
Risk classification thresholds: Low (1–8), Medium (9–27), High (28–64), Critical (65–125).
Assumptions & References
- Based on the multiplicative risk assessment model widely used in occupational health and safety (OHS) practice, consistent with OSHA Job Hazard Analysis guidelines (OSHA 3071).
- The three-factor model (Likelihood × Severity × Exposure) is derived from the Fine & Kinney method of quantitative risk assessment (W.T. Fine, 1971; Kinney & Wiruth, 1976).
- Risk score thresholds (Low, Medium, High, Critical) are based on common industry practice and may be adjusted by the organization's safety management system.
- All three factors are assumed to be independent variables contributing equally to overall risk.
- This calculator is intended as a screening tool. A qualified safety professional should review all High and Critical risk findings.
- Results should be documented in the formal JHA/JSA (Job Safety Analysis) record and reviewed by a supervisor or safety officer.
- Reference: OSHA Publication 3071 – Job Hazard Analysis; ANSI/AIHA Z10 Occupational Health and Safety Management Systems Standard.