Total Recordable Incident Rate (TRIR)
Calculate the number of OSHA-recordable incidents per 100 full-time employees per year.
DART Rate Calculator
Calculate the rate of incidents resulting in Days Away, Restricted duty, or Transfer per 100 full-time employees.
Lost Time Injury Frequency (LTIF / LTIR)
Calculate the frequency of injuries resulting in at least one full day away from work, excluding restricted-duty cases.
Severity Rate Calculator
Measure the total number of lost workdays per 100 full-time employees. This indicates how severe incidents are in terms of time lost.
Lost Workday Case Rate (LWCR)
Measure the number of cases resulting in lost workdays, normalized per 100 full-time employees. LWCR is a legacy metric that predates the current DART rate; it is still widely used in contractor prequalification and insurance audits.
OSHA 300 Summary Rates
Simultaneously calculate TRIR, DART Rate, and LTCR (Lost Time Case Rate) based on your OSHA 300 log data.
OSHA Incident Rate Calculator — Calculate TRIR, DART, LTIR & Severity Rates
Use our free OSHA incident rate calculator above to instantly compute your Total Recordable Incident Rate (TRIR), DART rate, Lost Time Injury Frequency (LTIF), Severity Rate, and Lost Workday Case Rate (LWCR). Whether you're an EHS manager preparing your OSHA 300A annual summary or a contractor filling out a prequalification questionnaire, understanding these calculations is essential for regulatory compliance and meaningful safety improvement. This guide walks you through each metric's formula, what the numbers actually mean, and how to use them to benchmark and improve your workplace safety program.
What Is an OSHA Incident Rate?
An OSHA incident rate is a standardized metric that quantifies the number of workplace injuries, illnesses, or fatalities relative to the total number of hours worked by all employees. The Occupational Safety and Health Administration (OSHA), under the U.S. Department of Labor, requires covered employers to record workplace injuries and illnesses on the OSHA 300 Log. The rates derived from this data—such as TRIR, DART, and LTIR—normalize incident counts per 200,000 hours worked (the equivalent of 100 full-time employees working for one year), making it possible to compare safety performance across companies and industries of any size.
These metrics are governed by 29 CFR Part 1904 (Recording and Reporting Occupational Injuries and Illnesses). Understanding how to calculate and interpret them accurately is a core competency for every safety professional, HR manager, and business owner.
What Counts as an OSHA Recordable Incident?
Before you can use any OSHA incident rate calculator, you must determine which incidents are "recordable." Per 29 CFR 1904.7, a work-related injury or illness is OSHA-recordable if it results in any of the following:
- Death
- Days away from work (the employee misses at least one day beyond the day of injury)
- Restricted work activity or job transfer
- Medical treatment beyond first aid (e.g., prescription medication, sutures, surgical procedures)
- Loss of consciousness
- Significant injury or illness diagnosed by a licensed health care professional (e.g., fracture, punctured eardrum, chronic disease)
First aid cases—such as applying bandages, using non-prescription medications, administering tetanus shots, or using wound closure strips—are not recordable, even if performed by a physician. Correctly distinguishing first aid from medical treatment is one of the most common sources of recordkeeping errors. When in doubt, refer to OSHA's recordkeeping guidelines.
Total Recordable Incident Rate (TRIR)
The Total Recordable Incident Rate (TRIR)—also called the Total Case Incident Rate (TCIR)—is the single most commonly cited safety metric in the United States. It captures the number of all OSHA-recordable incidents per 100 full-time equivalent (FTE) workers over a one-year period.
Why TRIR matters: TRIR provides a broad benchmark for overall safety performance. It is a required disclosure on many contractor prequalification forms (such as ISNetworld and Avetta), influences workers' compensation Experience Modification Rate (EMR), and is routinely reviewed during OSHA inspections. A TRIR significantly above your industry average can trigger heightened scrutiny, while a consistently low TRIR strengthens your competitive position when bidding for contracts.
DART Rate (Days Away, Restricted, or Transferred)
The DART Rate is a subset of TRIR. It exclusively counts incidents severe enough to result in one or more of the following: the employee missing work (days away), being restricted from performing their normal duties, or being transferred to a different job.
Why DART matters: OSHA uses DART rates to prioritize its Site-Specific Targeting (SST) program for inspections. Establishments with DART rates above the national average for their industry are more likely to receive an unannounced inspection. Because it filters out first-aid-only and medical-treatment-only cases, the DART rate gives a sharper view of incident severity and direct productivity impact than TRIR alone.
Lost Time Injury Frequency (LTIF / LTIR)
The Lost Time Injury Rate (LTIR) focuses exclusively on injuries that result in an employee missing at least one full day of work following the day of the incident. Unlike DART, it excludes restricted-duty and job-transfer cases, making it a narrower measure of injury severity that highlights direct absenteeism.
Global (ILO): LTIF = (Lost Time Injuries × 1,000,000) ÷ Total Hours Worked
Internationally, companies aligned with the International Labour Organization (ILO) standards or operating in regions such as Europe, the Middle East, and Australia typically use a 1,000,000-hour multiplier, yielding the Lost Time Injury Frequency (LTIF). Our OSHA incident rate calculator above lets you toggle between both standards.
Why LTIR/LTIF matters: It quantifies the immediate economic and human toll of your most severe injuries. If your LTIR is high relative to your DART rate, it means a large proportion of your serious cases are resulting in actual days away—a signal that return-to-work and restricted-duty programs may not be functioning effectively.
Severity Rate
While TRIR and DART measure the frequency of incidents, the Severity Rate measure the impact of those incidents in terms of total workdays lost. The standard normalized formula is:
This produces a rate expressed as the total number of lost workdays per 100 full-time equivalent employees per year. It is consistent with the normalization approach used for TRIR and DART, allowing direct comparison across organizations of different sizes. Note: Per OSHA standard 29 CFR 1904.7(b)(3)(viii), employers must cap the day count at 180 days (including days away and restricted days) for any single incident.
Why Severity Rate matters: A low TRIR combined with a high severity rate signals that while incidents are infrequent, they are catastrophic when they occur. This pattern often indicates systemic hazards in high-risk tasks—such as falls from height, confined-space incidents, or caught-in/between machinery events—that need immediate engineering controls and targeted retraining. Lowering your severity rate requires active case management, robust return-to-work programs, and thorough root-cause analysis of every lost-time case.
Note: Some organizations use an alternative metric—Average Days per Case (Total Lost Workdays ÷ Number of Lost-Time Cases)—to measure per-incident severity. While useful, this is a different calculation from the normalized severity rate shown here and in our calculator above.
Lost Workday Case Rate (LWCR)
The Lost Workday Case Rate (LWCR) is a legacy metric that predates OSHA's current DART rate. It measures the rate of cases (both injuries and illnesses) resulting in one or more lost workdays, normalized per 100 full-time employees.
OSHA formally replaced LWCR with the DART rate in 2002 when the revised recordkeeping rules under 29 CFR 1904 added "restricted duty" and "job transfer" categories. However, LWCR remains widely referenced in contractor prequalification systems (ISNetworld, Avetta, PEC Safety), insurance audits, and older corporate safety benchmarking programs. If you encounter LWCR requirements, our OSHA incident rate calculator above can compute it instantly.
Why the 200,000 Multiplier?
You'll notice that every OSHA rate formula uses a 200,000 multiplier. This number represents:
Normalizing rates against this constant allows organizations of any size—from a 10-person job site to a 50,000-employee enterprise—to compare their safety records on an apples-to-apples basis against industry benchmarks published by the Bureau of Labor Statistics (BLS). Without normalization, a company with 5,000 employees would naturally report more total incidents than a company with 50, making raw numbers meaningless for comparison.
Step-by-Step TRIR Calculation Example
Let's walk through a concrete example to demonstrate how our OSHA incident rate calculator works:
📊 Scenario: ABC Manufacturing — Annual Safety Data
- Number of employees: 250
- Total hours worked by all employees: 500,000 hours
- Total OSHA-recordable incidents: 8 (including 3 medical-treatment-only, 3 restricted-duty, and 2 days-away cases)
- DART cases: 5 (3 restricted-duty + 2 days-away)
- Lost Time cases (days away only): 2
Step 1: Calculate TRIR
TRIR = (8 × 200,000) ÷ 500,000 = 1,600,000 ÷ 500,000 = 3.20
Interpretation: ABC Manufacturing had 3.20 recordable incidents per 100 full-time employees.
Step 2: Calculate DART Rate
DART = (5 × 200,000) ÷ 500,000 = 1,000,000 ÷ 500,000 = 2.00
Interpretation: 2.00 incidents per 100 FTE resulted in days away, restricted duty, or transfer.
Step 3: Calculate LTCR (Lost Time Case Rate)
LTCR = (2 × 200,000) ÷ 500,000 = 400,000 ÷ 500,000 = 0.80
Interpretation: 0.80 cases per 100 FTE resulted in actual days away from work.
Step 4: Analyze the Relationships
DART-to-TRIR ratio: 2.00 ÷ 3.20 = 62.5% — meaning 62.5% of all recordable incidents were severe enough to cause days away, restricted duty, or transfer. A ratio above 60% suggests that when incidents occur, they tend to be serious. ABC Manufacturing should investigate whether their first-aid and early-intervention programs are catching hazards before they escalate.
OSHA Incident Rate Benchmarks by Industry
The Bureau of Labor Statistics (BLS) publishes annual incident rates by NAICS industry code through its Survey of Occupational Injuries and Illnesses (SOII). Below are approximate averages based on recent BLS data. Use these as general reference points only—exact values change annually and vary by establishment size.
| Industry (NAICS) | Approx. TRIR | Approx. DART |
|---|---|---|
| All Private Industry | 2.7 | 1.5 |
| Construction (23) | 2.8 | 1.4 |
| Manufacturing (31–33) | 3.3 | 1.8 |
| Warehousing & Storage (493) | 4.8 | 3.5 |
| Healthcare & Social Assistance (62) | 4.5 | 2.5 |
| Retail Trade (44–45) | 3.1 | 1.6 |
| Finance & Insurance (52) | 0.5 | 0.3 |
| Agriculture (11) | 5.0 | 2.8 |
| Transportation (48–49) | 4.0 | 2.5 |
Source: BLS Injuries, Illnesses, and Fatalities (IIF) program. Data is approximate and based on recent published SOII tables. Always verify against the latest BLS release for your specific NAICS sub-code.
As you can see, a TRIR of 3.0 would be considered excellent in warehousing but well above average in finance. This is precisely why our OSHA incident rate calculator includes a disclaimer to compare against industry-specific data rather than relying on universal "good/bad" thresholds.
TRIR vs. DART vs. LTIR — What's the Difference?
These three metrics are related but measure different things. Understanding their relationship is critical for accurate safety analysis:
| Feature | TRIR | DART Rate | LTIR |
|---|---|---|---|
| Full Name | Total Recordable Incident Rate | Days Away, Restricted, or Transferred Rate | Lost Time Injury Rate |
| Cases Counted | All OSHA-recordable incidents | Only cases with days away, restricted duty, or transfer | Only cases with days away from work |
| Includes Medical-Treatment-Only? | Yes | No | No |
| Includes Restricted Duty? | Yes | Yes | No |
| Includes Days Away? | Yes | Yes | Yes |
| Multiplier | 200,000 | 200,000 | 200,000 (U.S.) or 1,000,000 (Global) |
| OSHA Uses for SST Inspections? | No (historically) | Yes — primary metric | No |
| Scope | Broadest | Moderate | Narrowest |
Key insight: TRIR ≥ DART ≥ LTIR — always. If your data shows otherwise, there is an error in your OSHA 300 log categorization. A healthy DART-to-TRIR ratio typically falls between 40–60%, meaning fewer than half of all recordable cases are severe enough to cause days away, restricted duty, or transfer.
Leading Indicators vs. Lagging Indicators
TRIR, DART, LTIR, Severity Rate, and LWCR are all lagging indicators—they measure incidents after they have already occurred. While they are indispensable for OSHA reporting, benchmarking, and historical trend analysis, relying on lagging indicators alone is like driving by looking exclusively in the rearview mirror.
World-class safety programs balance lagging indicators with leading indicators—proactive measures that predict and prevent future incidents:
- Safety audits and inspections completed vs. planned
- Near-miss reports submitted per employee per month
- Safety training completion rates and knowledge assessment scores
- Hazard observations and corrective-action closure rates
- Behavior-Based Safety (BBS) observation counts
- Safety meeting attendance and engagement
- Pre-task hazard analysis (JHA/JSA) completion rates
When leading indicators improve, lagging indicators like TRIR and DART typically follow. Track both in your safety management system for a complete picture of your safety program's health.
Common Mistakes When Calculating OSHA Incident Rates
Even experienced safety professionals make calculation errors. Avoid these common pitfalls when using an OSHA incident rate calculator:
- Miscounting recordable incidents: The most frequent error is misclassifying first-aid cases as recordable (or vice versa). Review 29 CFR 1904.7 carefully. For example, butterfly bandages and Steri-Strips are first aid; sutures (stitches) are medical treatment and therefore recordable.
- Using employee headcount instead of hours worked: The denominator must be actual hours worked by all employees, not simply the number of employees multiplied by 2,000. Include overtime, exclude vacation, holidays, and sick leave.
- Including non-work-related cases: Only injuries and illnesses that meet OSHA's work-relatedness criteria (29 CFR 1904.5) should be counted.
- Forgetting temporary and contract workers: If your company supervises temporary employees on a day-to-day basis, their hours and injuries should be included in your rates, not the staffing agency's.
- Double-counting across metrics: Remember that DART is a subset of TRIR, and LTC (days-away cases) is a subset of DART. Never add them together.
- Confusing LWCR with DART: LWCR is a legacy metric that does not include restricted-duty or transfer cases. If a form asks for "DART rate," do not provide your LWCR.
- Applying universal benchmarks without industry context: A TRIR of 4.0 is above average for all private industry but below average for warehousing. Always compare against your NAICS code.
How to Reduce Your OSHA Incident Rate
Calculating your rates is only the beginning. Here are evidence-based strategies to systematically lower your TRIR, DART, and severity rates:
- Implement a robust near-miss reporting program: Research shows that for every serious injury, there are approximately 300 near-miss events (Heinrich's Triangle). Capturing and investigating near misses before they become injuries is the most effective prevention strategy.
- Follow the hierarchy of controls: Prioritize elimination and substitution of hazards over administrative controls and PPE. Engineering controls (guards, ventilation, fall-arrest systems) are far more reliable than relying on human behavior.
- Strengthen your return-to-work (RTW) program: A well-designed restricted-duty program reduces lost-time days, lowering your severity rate. Employees who return to modified duty heal faster and are less likely to develop chronic conditions.
- Conduct regular Job Hazard Analyses (JHAs): Systematically identify hazards in each job task and implement controls before an incident occurs.
- Invest in targeted training: Focus on your highest-risk activities. OSHA's Top 10 Most Cited Standards (Fall Protection, Hazard Communication, Scaffolding, Lockout/Tagout, etc.) reveal where most violations and injuries occur.
- Conduct root-cause analysis on every recordable: Use structured methods (5 Whys, fishbone diagrams, TapRooT®) to identify systemic failures, not just immediate causes.
- Engage leadership: Management commitment—visible safety walks, resource allocation, and accountability—is the single strongest predictor of safety culture maturity.
Leveraging Your OSHA 300 Log Data for Continuous Improvement
Using our unified OSHA 300 Summary calculator above is the first step. Simply having low numbers isn't enough—successful EHS programs use these metrics to drive continuous improvement:
- Identify blind spots: A significant gap between TRIR and DART may indicate that your first-aid and early-intervention programs are working well—most incidents are being managed before they escalate. However, if the DART rate is nearly as high as the TRIR, it suggests almost every incident is severe, which is a red flag.
- Direct training budgets: High severity rates often correlate with hazards in specific high-risk tasks. Align your training investment with the activities driving the most lost days—whether that's Fall Protection, Confined Space Entry, or Powered Industrial Trucks.
- Benchmark against competitors: The BLS publishes annual incident rates by NAICS code, enabling you to see exactly where you stand relative to your industry. Falling below your industry average strengthens your position when bidding for contracts or negotiating insurance premiums.
- Trigger root-cause investigations: A spike in your LWCR or severity rate should immediately prompt a formal investigation into why existing hazard controls (such as PPE, machine guards, or work procedures) are failing to protect workers.
- Track trends over time: Calculate rates monthly or quarterly, not just annually. Trend analysis reveals whether your safety program's trajectory is improving, plateauing, or declining—before the annual OSHA 300A summary forces you to confront the numbers.
Frequently Asked Questions (FAQ)
What is a good OSHA incident rate?
There is no single universal "good" rate. A good OSHA incident rate depends on your industry. For example, the all-private-industry average TRIR is approximately 2.7, but warehousing averages around 4.8 while finance averages around 0.5. As a general target, you should aim to be at or below the average for your specific NAICS industry code, as published by the Bureau of Labor Statistics (BLS). Many world-class safety programs target a TRIR below 1.0, but this varies significantly by sector.
How do you calculate OSHA TRIR?
TRIR is calculated using the formula: (Number of OSHA-Recordable Incidents × 200,000) ÷ Total Hours Worked by all employees. The 200,000 multiplier normalizes the rate to 100 full-time equivalent employees (40 hours/week × 50 weeks/year). For example, if you had 5 recordable incidents and 400,000 total hours worked: TRIR = (5 × 200,000) ÷ 400,000 = 2.50.
What is the difference between TRIR and DART?
TRIR counts all OSHA-recordable incidents—including medical-treatment-only cases, restricted duty, job transfers, and days-away cases. DART only counts the subset of incidents that result in Days Away from work, Restricted duty, or job Transfer. DART is always less than or equal to TRIR. OSHA uses the DART rate (not TRIR) for its Site-Specific Targeting inspection program.
What does the 200,000 multiplier mean in OSHA calculations?
The 200,000 figure represents the total hours worked by 100 full-time employees in one year: 100 employees × 40 hours/week × 50 weeks/year = 200,000 hours. This standardization allows companies of any size to compare safety performance on a per-100-employee basis. Without this normalization, a company with 10,000 employees would always appear less safe than a company with 10 employees simply due to scale.
What is a recordable incident under OSHA?
Per 29 CFR 1904.7, a work-related injury or illness is OSHA-recordable if it results in: death, days away from work, restricted work activity or job transfer, medical treatment beyond first aid, loss of consciousness, or a significant injury or illness diagnosed by a physician or licensed healthcare professional. First-aid-only cases are not recordable, even if provided by a doctor.
How does OSHA calculate the DART rate?
The DART rate formula is: (Number of DART Cases × 200,000) ÷ Total Hours Worked. DART cases include any recordable incident that resulted in at least one day away from work, one day of restricted work activity, or a job transfer. Medical-treatment-only cases are excluded from DART.
Do I include temporary workers in my OSHA incident rate?
If your company supervises temporary/contract employees on a day-to-day basis, their hours worked and any injuries they sustain should generally be included in your company's OSHA 300 log and rate calculations—not the staffing agency's. OSHA's guidance on this matter is detailed in its temporary worker bulletin. Both the host employer and staffing agency share responsibility, but the host employer typically records the case.
How often should I calculate my OSHA incident rates?
At a minimum, you must calculate annual rates for your OSHA 300A Annual Summary (due by February 1 of the following year, posted through April 30). However, best practice is to calculate rates monthly or quarterly so you can identify trends early and take corrective action before year-end. Many companies also calculate trailing 12-month rates to smooth out seasonal fluctuations.
Conclusion
Understanding how to accurately use an OSHA incident rate calculator to compute TRIR, DART, LTIR, Severity Rate, and LWCR empowers your safety team to make data-driven decisions. Maintaining an accurate OSHA 300 log isn't just a regulatory formality mandated by 29 CFR 1904—it is a critical diagnostic tool for evaluating the health of your workplace safety program. By tracking these metrics consistently, benchmarking against your industry's BLS averages, balancing them with proactive leading indicators, and taking swift corrective action when rates climb, you can proactively prevent injuries, protect your workforce, reduce costly downtime, and build a resilient safety culture that stands up to OSHA scrutiny.
📚 Sources & References
- 29 CFR Part 1904 — Recording and Reporting Occupational Injuries and Illnesses, Electronic Code of Federal Regulations (eCFR).
- 29 CFR 1904.7 — General Recording Criteria for Cases, OSHA.
- Injuries, Illnesses, and Fatalities (IIF) Program, Bureau of Labor Statistics, U.S. Department of Labor.
- OSHA Recordkeeping, Occupational Safety and Health Administration.
- OSHA Recordkeeping Forms (300, 300A, 301), OSHA.
- Site-Specific Targeting (SST) Program Directive, OSHA.