TRIR
Total Recordable Incident Rate, normalized by the selected exposure-hour base.
Decision-support notice: This calculator summarizes safety performance from user-entered data. Verify definitions, legal requirements, reporting bases, and all critical events before relying on results.
Reference
Formula used
Core formulas, score normalization, weighting, and override logic.
Exposure-based rates
TRIR = (Recordable Cases × Selected Rate Base) ÷ Included Hours Worked
DART = ((Days Away Cases + Restricted Cases + Transfer Cases) × Selected Rate Base) ÷ Included Hours Worked
LTIFR = (Lost-Time Injuries × Selected Frequency Base) ÷ Included Hours Worked
Severity Rate = ((Days Away + Restricted Days) × Selected Rate Base) ÷ Included Hours Worked
The included-hours denominator combines employee hours and, when enabled, contractor hours. Rate bases are configurable so the application can support organizations using 200,000 hours, 1,000,000 hours, or another accepted internal basis.
Normalized component scoring
Lower-is-better indicators receive high scores when actual performance meets or beats the target, then decline progressively as the result moves above target. Higher-is-better indicators receive points according to target attainment. Percentage inputs are limited to the zero-to-one-hundred range before scoring. Audit, corrective-action, and training penalties reduce scores when repeat findings, overdue actions, critical backlog, expired certifications, or overdue training are present.
SPI = Σ(Component Score × Component Weight) ÷ Σ(Component Weights)
The default model uses incident performance at 25%, severity at 15%, leading indicators at 20%, corrective actions at 15%, training at 10%, and audit or compliance performance at 15%. The user may change these values, but the total must equal 100%.
Critical-event governance
Critical overrides protect the integrity of the index. A fatality can cap the score at 25, a regulatory shutdown at 20, an uncontrolled critical hazard at 40, a major process-safety event at 35, and a serious environmental release at 50. Critical overdue actions cap the score at 60. Repeated lockout or tagout violations subtract points. These controls are intentionally conservative because an average score should never obscure a severe event.
Instructions
How to use this calculator
A practical workflow for consistent manufacturing safety reviews.
Define one reporting scope
Start by selecting a single facility, department, line, or comparable operating unit. Use the same scope for workforce, exposure hours, incidents, training, audits, and costs. Mixing a plant-wide numerator with a department-only denominator produces misleading rates. Enter the reporting period clearly so saved scenarios remain comparable.
Confirm the exposure denominator
Enter actual hours worked when available. Decide whether contractor exposure should be included, then apply that decision consistently to incident counts. If contractor incidents are included but contractor hours are excluded, rates will be overstated. Production units and machine hours are optional, but they help compare operations with different staffing or throughput.
Enter lagging indicators carefully
Use your organization’s approved recordability definitions. Verify that lost-time, restricted, transfer, and medical-treatment cases reconcile with total recordables. Enter days away and restricted days using the same counting convention throughout the organization. Do not omit fatalities, shutdowns, serious releases, or major process-safety events because they materially change interpretation.
Balance the index with leading indicators
Leading indicators should reflect useful preventive work, not activity for its own sake. Near-miss and observation counts are normalized by exposure hours. Planned-versus-completed measures are useful for inspections, toolbox talks, maintenance, emergency drills, and risk assessments. Strong performance requires both volume and quality, so the calculator also considers overdue actions, repeat findings, and effectiveness verification.
Review training and authorization
Enter required and completed training, workforce coverage, new-hire orientation, operator certification, contractor induction, and assessment pass rates. Expired credentials and overdue refresher training reduce the training score. Safety-critical equipment should only be operated by authorized personnel with current competence evidence.
Use audit scores consistently
Convert audit results to percentages using a documented method. Avoid comparing a strict field-verification audit with a lenient checklist unless scoring criteria are aligned. Repeat findings, major findings, and regulatory notices create penalties because unresolved systemic issues increase risk even when the average audit percentage looks strong.
Set weights before reviewing the outcome
Agree on component weights through governance, not after seeing a score. Frequent weight changes can make trends meaningless. Save the selected model with every report and disclose changes in management reviews. Critical-event overrides should remain enabled unless a competent governance body approves a different rule.
Interpret, verify, and act
Use the overall index as a signal, then inspect component scores, rates, warnings, module results, and recommendations. Investigate the lowest-scoring areas. Export CSV or JSON for recordkeeping, and use the print function to create a PDF through the browser. A good score does not prove compliance or eliminate risk; it supports prioritization and accountability.
Risk tools
Example five-by-five risk matrix
Use your approved risk criteria when converting hazards into action priorities.
| Likelihood ↓ / Consequence → | 1 Insignificant | 2 Minor | 3 Moderate | 4 Major | 5 Catastrophic |
|---|---|---|---|---|---|
| 5 Almost certain | 5 | 10 | 15 | 20 | 25 |
| 4 Likely | 4 | 8 | 12 | 16 | 20 |
| 3 Possible | 3 | 6 | 9 | 12 | 15 |
| 2 Unlikely | 2 | 4 | 6 | 8 | 10 |
| 1 Rare | 1 | 2 | 3 | 4 | 5 |
Glossary
Safety performance terminology
Definitions used throughout the calculator and report.
DART
Rate for cases involving days away, restricted work, or job transfer.
LTIFR
Lost-Time Injury Frequency Rate, often normalized per one million hours.
Severity rate
Lost and restricted workdays normalized by the selected rate base.
Near miss
An unplanned event that caused no harm but had credible potential.
Safety observation
A documented observation of safe work or an improvement opportunity.
Stop-work intervention
A good-faith pause of work because conditions appeared unsafe.
Toolbox talk
A short, focused safety discussion connected to current work.
Job safety analysis
A task-level breakdown of hazards, controls, and safe steps.
Preventive maintenance
Planned work intended to maintain safe and reliable equipment.
Corrective action
A defined action addressing a finding, incident cause, or control gap.
Effectiveness verification
Evidence that an action solved the issue without creating new risk.
Repeat finding
A finding that recurs after an earlier action was closed.
Critical overdue action
A high-significance action that remains open past its due date.
Hazard control rate
Percentage of identified hazards eliminated or placed under verified control.
Residual risk
Risk remaining after controls are implemented and verified.
Management of change
Structured review of safety impacts before or during a change.
Permit to work
Formal authorization for defined high-risk work under specified controls.
Machine guarding
Physical or sensing safeguards that prevent access to dangerous motion.
Lockout/tagout
Isolation and control of hazardous energy before servicing or maintenance.
Process safety
Management of catastrophic release, fire, explosion, and major process hazards.
Combustible dust
Fine particulate that can create fire or explosion hazards when dispersed.
Leading indicator
A preventive or predictive measure associated with risk control activity.
Lagging indicator
A measure describing events or losses that have already occurred.
Score cap
A maximum permitted overall score after a severe condition or event.
Exposure hours
Hours worked by the population included in the incident numerator.
Recordable case
A case meeting the organization’s applicable recordability requirements.
Restricted case
A case in which normal work is restricted because of injury or illness.
Days away
Days the worker cannot perform work because of a work-related case.
Audit average
Average of enabled audit or compliance percentage scores before penalties.
Training coverage
Percentage of people current on all required safety learning.
Operator authorization
Documented permission to operate specified equipment after competence checks.
Contractor induction
Site-specific safety onboarding completed before contractor work begins.
Production normalization
Expressing safety events relative to output, machine time, or another activity basis.
Direct incident cost
Medical, damage, legal, lost production, and other directly assigned costs.
Indirect cost
Estimated secondary cost, often modeled as a multiple of direct incident cost.
Preventive spending
Resources used to reduce risk before incidents occur.
Reactive spending
Resources consumed because incidents, failures, or enforcement already occurred.
Weighting model
The percentage contribution assigned to each SPI component.
Benchmark
A target or comparison point used to interpret actual performance.
Critical override
A rule that limits or reduces the index when severe conditions exist.
Regulatory shutdown
A formal stop order or operating restriction imposed by an authority.
Serious release
A significant environmental or process release requiring escalation.
Risk assessment
A documented evaluation of hazards, consequences, likelihood, and controls.
High-risk permit
Formal authorization for work with elevated hazard potential.
Safety-critical failure
Failure of equipment or controls intended to prevent severe outcomes.
Housekeeping score
Assessment of storage, cleanliness, access, spills, and trip hazards.
Ergonomics score
Assessment of force, posture, repetition, duration, and task design.
Emergency preparedness
Readiness of plans, people, equipment, drills, and communications.
Preventive-to-reactive ratio
Preventive and training spend divided by modeled incident-related cost.
Governance
Management review checklist
Use this checklist before approving or distributing the calculated index.
| # | Area | Control question | Review |
|---|---|---|---|
| 1 | Leadership | Senior leaders review critical events and overdue actions at a defined cadence. | □ Yes □ No □ N/A |
| 2 | Leadership | Safety accountabilities are included in role descriptions and performance reviews. | □ Yes □ No □ N/A |
| 3 | Planning | Annual objectives include both leading and lagging indicators. | □ Yes □ No □ N/A |
| 4 | Planning | Targets are documented before the reporting period begins. | □ Yes □ No □ N/A |
| 5 | Data quality | Incident classifications are reviewed by competent personnel. | □ Yes □ No □ N/A |
| 6 | Data quality | Exposure hours reconcile with payroll or timekeeping records. | □ Yes □ No □ N/A |
| 7 | Data quality | Contractor numerator and denominator rules are applied consistently. | □ Yes □ No □ N/A |
| 8 | Data quality | Duplicate events are removed before calculation. | □ Yes □ No □ N/A |
| 9 | Risk | Critical hazards have named owners and interim controls. | □ Yes □ No □ N/A |
| 10 | Risk | Risk assessments are reviewed after incidents and significant changes. | □ Yes □ No □ N/A |
| 11 | Risk | Residual risk acceptance follows delegated authority. | □ Yes □ No □ N/A |
| 12 | Risk | Management-of-change reviews cover people, process, equipment, and procedures. | □ Yes □ No □ N/A |
| 13 | Training | Training matrices reflect current roles and equipment. | □ Yes □ No □ N/A |
| 14 | Training | Expired safety-critical credentials automatically restrict authorization. | □ Yes □ No □ N/A |
| 15 | Training | Competence is verified, not inferred from attendance alone. | □ Yes □ No □ N/A |
| 16 | Audit | Audit protocols define scoring and evidence requirements. | □ Yes □ No □ N/A |
| 17 | Audit | Repeat findings receive stronger escalation than new minor findings. | □ Yes □ No □ N/A |
| 18 | Audit | Closed findings are sampled for field effectiveness. | □ Yes □ No □ N/A |
| 19 | Corrective actions | Every action has an owner, due date, priority, and verification method. | □ Yes □ No □ N/A |
| 20 | Corrective actions | Critical overdue actions are escalated to senior management. | □ Yes □ No □ N/A |
| 21 | Corrective actions | Extension approvals include temporary controls and revised risk. | □ Yes □ No □ N/A |
| 22 | Operations | Pre-start checks are defined for safety-critical equipment. | □ Yes □ No □ N/A |
| 23 | Operations | Permit controls are verified in the field before work begins. | □ Yes □ No □ N/A |
| 24 | Operations | Production pressure does not bypass isolation or guarding controls. | □ Yes □ No □ N/A |
| 25 | Maintenance | Safety-critical preventive maintenance is separately identified. | □ Yes □ No □ N/A |
| 26 | Maintenance | Backlog risk is reviewed, prioritized, and documented. | □ Yes □ No □ N/A |
| 27 | Maintenance | Post-maintenance testing confirms protective functions. | □ Yes □ No □ N/A |
| 28 | Contractors | Contractors are prequalified using risk-based criteria. | □ Yes □ No □ N/A |
| 29 | Contractors | Site induction addresses local hazards and emergency arrangements. | □ Yes □ No □ N/A |
| 30 | Contractors | Contractor performance is reviewed before future award decisions. | □ Yes □ No □ N/A |
| 31 | Emergency | Credible emergency scenarios are documented and exercised. | □ Yes □ No □ N/A |
| 32 | Emergency | Drill observations become tracked corrective actions. | □ Yes □ No □ N/A |
| 33 | Emergency | Emergency equipment inspection records are current. | □ Yes □ No □ N/A |
| 34 | Reporting | Management reports disclose changes to methods, targets, and weights. | □ Yes □ No □ N/A |
| 35 | Reporting | A favorable SPI never cancels investigation of severe events. | □ Yes □ No □ N/A |
| 36 | Reporting | The report distinguishes data gaps from true zero performance. | □ Yes □ No □ N/A |
| 37 | Improvement | Recommendations are assigned to accountable owners. | □ Yes □ No □ N/A |
| 38 | Improvement | Benefits and unintended consequences are reviewed after changes. | □ Yes □ No □ N/A |
| 39 | Improvement | Lessons learned are shared across comparable facilities. | □ Yes □ No □ N/A |
| 40 | Governance | Score bands and override rules are approved and version controlled. | □ Yes □ No □ N/A |