Injury Severity Score Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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In acute care, a score can support a rapid shared language, but it cannot replace the patient in front of you. Injury Severity Score Calculator calculates the specific bedside score or index from the fields shown in this tool.

What this calculator does

Injury Severity Score Calculator uses Head / neck AIS, Face AIS, Chest AIS, Abdomen AIS, Extremity / pelvic girdle AIS, and External AIS to produce the injury severity score used by this calculator. It only uses the fields shown in this calculator; it does not silently add tests, diagnoses, symptoms, or clinical variables that are absent from the interface. ISS flow uses the highest AIS score in each of six body regions; the three highest region scores are squared and summed, with AIS 6 forcing ISS 75.

How to use it

Enter or select Head / neck AIS, Face AIS, Chest AIS, Abdomen AIS, Extremity / pelvic girdle AIS, and External AIS. Use the actual observations or labs from the assessment time point intended by the score. If an input is unknown, it is better to leave the calculation unresolved than to invent a value.

How the calculation works

The calculator takes the highest AIS value entered for each of six body regions, squares the three highest regional scores, and sums them. If any region has AIS 6, the Injury Severity Score is forced to 75.

Example

Using the calculator’s prefilled demonstration values, the primary output is 0 points, labeled “Injury Severity Score”; Top three AIS is 0, 0, 0. That sample is useful for checking the calculation path, but real interpretation should use verified measurements from the same clinical or study context.

How to interpret the result

Read injury severity score as a structured snapshot of the entered data. The score can support communication or risk stratification, but deterioration, resuscitation needs, clinical gestalt, and diagnoses not represented in the variables can override the numeric category.

Limitations and notes

These tools summarize selected variables at one moment. They can miss rapidly evolving disease, treatment response, contraindications, and diagnoses outside the score. If the patient is unstable or the clinical concern is high, care should never be delayed by a calculator.