{
  "id": "trir",
  "version": "840ad37ab268",
  "status": "published",
  "name": "TRIR Calculator",
  "question": "What is our TRIR incident rate?",
  "summary": "Works out OSHA’s total recordable incident rate (TRIR) and the DART rate per 100 full-time workers from the recordable cases and the hours worked in a year.",
  "category": "everyday-life",
  "url": "https://www.acalculator.org/everyday-life/trir-calculator",
  "markdown": "https://www.acalculator.org/everyday-life/trir-calculator.md",
  "kind": "function",
  "method": "TRIR = recordable cases × 200,000 ÷ hours worked; DART rate = DART cases × 200,000 ÷ hours worked.",
  "assumptions": [
    "200,000 hours is 100 full-time employees working 40 hours a week for 50 weeks.",
    "With a head count, each full-time employee counts as 2,000 hours a year; payroll hours are more accurate.",
    "Cases are those recorded on OSHA Form 300 under 29 CFR 1904."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "cases": {
        "title": "Recordable cases",
        "description": "Work-related injuries and illnesses recorded on OSHA Form 300 for the year.",
        "type": "integer",
        "minimum": 0,
        "maximum": 1000000000
      },
      "dart": {
        "title": "DART cases",
        "description": "Optional: the recordable cases with days away from work, restricted work or a job transfer.",
        "type": "integer",
        "minimum": 0,
        "maximum": 1000000000
      },
      "by": {
        "title": "I know",
        "description": "The total hours all employees worked, or the number of full-time employees.",
        "type": "string",
        "enum": [
          "hours",
          "employees"
        ]
      },
      "hours": {
        "title": "Hours worked",
        "description": "Total hours all employees actually worked in the year, from payroll.",
        "type": "number",
        "minimum": 1,
        "maximum": 1000000000000
      },
      "emp": {
        "title": "Full-time employees",
        "description": "The average number of full-time employees; each counts as 2,000 hours a year.",
        "type": "number",
        "minimum": 0.01,
        "maximum": 100000000
      }
    }
  },
  "outputs": {
    "trir": {
      "label": "TRIR",
      "description": "Recordable cases × 200,000 ÷ hours worked.",
      "format": "number"
    },
    "dartRate": {
      "label": "DART rate",
      "description": "DART cases × 200,000 ÷ hours worked.",
      "format": "number"
    },
    "hoursUsed": {
      "label": "Hours worked",
      "description": "The hours typed, or employees × 2,000.",
      "format": "number"
    },
    "meaning": {
      "label": "In words",
      "description": "The TRIR as cases per 100 full-time workers a year.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "cases": 3,
      "by": "hours",
      "hours": 150000,
      "emp": 75
    },
    "outputs": {
      "trir": 4,
      "hoursUsed": 150000,
      "meaning": "About 4 recordable cases for every 100 full-time workers in a year"
    },
    "text": "3 recordable cases in 150,000 hours worked is a TRIR of 4."
  },
  "examples": [
    {
      "given": {
        "cases": 3,
        "by": "hours",
        "hours": 150000
      },
      "expect": {
        "trir": 4,
        "hoursUsed": 150000
      },
      "source": "OSHA, Clarification on how the formula is used by OSHA to calculate incident rates (2016-08-23): (injuries and illnesses × 200,000) ÷ employee hours worked; 200,000 is 100 employees working 40 hours a week, 50 weeks a year, https://www.osha.gov/laws-regs/standardinterpretations/2016-08-23 (retrieved 2026-10-03); hand calculation in content.mdx: 3 × 200,000 ÷ 150,000 = 4.00"
    },
    {
      "given": {
        "cases": 5,
        "dart": 2,
        "by": "employees",
        "emp": 50
      },
      "expect": {
        "hoursUsed": 100000,
        "trir": 10,
        "dartRate": 4
      },
      "source": "OSHA, Clarification on how the formula is used by OSHA to calculate incident rates (2016-08-23): (injuries and illnesses × 200,000) ÷ employee hours worked; 200,000 is 100 employees working 40 hours a week, 50 weeks a year, https://www.osha.gov/laws-regs/standardinterpretations/2016-08-23 (retrieved 2026-10-03); hand calculation in content.mdx: 50 × 2,000 = 100,000 hours; 5 × 200,000 ÷ 100,000 = 10.00; 2 × 200,000 ÷ 100,000 = 4.00"
    },
    {
      "given": {
        "cases": 7,
        "dart": 3,
        "by": "hours",
        "hours": 412345
      },
      "expect": {
        "trir": 3.39521517176151,
        "dartRate": 1.4550922164692188
      },
      "source": "OSHA, Clarification on how the formula is used by OSHA to calculate incident rates (2016-08-23): (injuries and illnesses × 200,000) ÷ employee hours worked; 200,000 is 100 employees working 40 hours a week, 50 weeks a year, https://www.osha.gov/laws-regs/standardinterpretations/2016-08-23 (retrieved 2026-10-03); hand calculation in content.mdx: 7 × 200,000 ÷ 412,345 = 3.40; 3 × 200,000 ÷ 412,345 = 1.46"
    }
  ],
  "sources": [
    "OSHA, Clarification on how the formula is used by OSHA to calculate incident rates, standard interpretation of 2016-08-23 ((number of injuries and illnesses × 200,000) ÷ employee hours worked = incidence rate; 200,000 is the hours of 100 employees working 40 hours a week, 50 weeks a year). https://www.osha.gov/laws-regs/standardinterpretations/2016-08-23 (retrieved 2026-10-03)"
  ],
  "related": [
    "productivity"
  ],
  "changelog": []
}