Accident Severity Index Calculator

Evaluate incidents with flexible scoring and exposure normalization. Compare outcomes, costs, and downtime across periods. Build stronger controls using consistent accident severity measurement methods.

Enter Accident and Exposure Data

Large screens show three columns, medium screens show two, and mobile shows one.

Custom Severity Weights

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Formula Used

Weighted Incident Score = (Fatalities × Fatality Weight) + (Permanent Disabilities × Permanent Weight) + (Lost Time Injuries × LTI Weight) + (Restricted Cases × Restricted Weight) + (Medical Treatment Cases × Medical Weight) + (First Aid Cases × First Aid Weight) + (Near Misses × Near Miss Weight)

Lost Day Burden = (Days Lost × Lost Day Weight) + (Restricted Duty Days × Restricted Day Weight)

Cost Burden = (Property Damage Cost + Environmental Cost + Legal Cost) ÷ Cost Divisor

Raw Severity Score = Weighted Incident Score + Lost Day Burden + Cost Burden

Accident Severity Index = Raw Severity Score × (Base Normalization Hours ÷ Hours Worked)

This model is a configurable management index. It helps compare periods, sites, and business units using one consistent severity framework.

How to Use This Calculator

  1. Enter incident counts for fatalities, disabilities, injuries, treatment cases, first aid cases, and near misses.
  2. Add operational impact values such as lost days, restricted duty days, and related costs.
  3. Enter hours worked and employees exposed for normalization and additional management ratios.
  4. Adjust weights if your organization uses different severity priorities.
  5. Click the calculate button to show the result above the form.
  6. Use the CSV and PDF buttons to export the summary and chart.

Example Data Table

Period Fatalities LTI Restricted Medical Near Misses Days Lost Total Cost Hours Worked Illustrative ASI
January 0 1 2 3 6 12 $17,000 45,000 310.22
February 0 1 1 2 4 6 $8,000 50,000 191.20
March 0 0 1 1 3 2 $3,000 52,000 84.62
April 0 1 0 1 2 20 $40,000 47,000 306.38

FAQs

1. What does the Accident Severity Index measure?

It measures the combined impact of accident counts, lost days, and financial consequences. The calculator converts these into a single normalized management score for easier comparison across periods or locations.

2. Is this the same as a legal reporting rate?

No. This is a configurable management index. It supports internal risk analysis and prioritization, while legal reporting often follows fixed definitions and regulatory formulas.

3. Why are custom weights included?

Different organizations treat outcomes differently. Some place heavier emphasis on fatalities, while others prioritize lost time, restricted work, or cost impact. Custom weights reflect your internal risk philosophy.

4. Why does the calculator use base normalization hours?

Base hours let you compare units with different exposure levels. A common choice is 200,000 hours, but you can use another base that matches your internal reporting standard.

5. Should near misses be part of severity?

They can be. Near misses usually carry low weight, but including them helps highlight weak controls and recurring exposure patterns before serious injuries happen.

6. What costs should I include?

Include direct accident-related costs that matter to your analysis, such as property damage, environmental cleanup, fines, legal cost, contractor impact, and similar measurable financial consequences.

7. How should I interpret the severity bands?

The bands provide quick management guidance. Low means limited impact, while Severe or Critical signals urgent review of controls, exposure conditions, and corrective actions.

8. Can I compare departments with this calculator?

Yes. That is one of its best uses. Keep the same weights, divisor, and normalization base across departments so the comparison stays fair and consistent.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.