Injury Severity Score Calculator
Pick each injury from the Ontario Ministry of Health / OMA examples, or add your own with an AIS score. The ISS updates as you go.
Examples from Table 1 of the Ontario MOH / OMA E420 billing brief (AAAM AIS 2015). Confirm scores against the AIS dictionary.
How the ISS is calculated
Take the highest AIS in each body region, then square and add the three highest regions.
All limbs and the pelvic girdle are one region. An open femur and a closed tibia only count once.
Spine: cervical → Head/neck, thoracic → Chest, lumbar → Abdomen.
Lacerations, contusions, abrasions and burns go under External, wherever they are on the body.
Any AIS 6 injury sets the ISS to 75.
E420 needs ISS >15 (age 16+) or >12 (under 16), with services on the day of trauma or within 24 hours.
For decision support only. This tool adds up the AIS scores you enter. It does not assign or certify AIS 2015 codes or guarantee OHIP payment. Nothing you enter leaves this page.