Glasgow Coma Scale Calculator
The Glasgow Coma Scale (GCS), developed by Teasdale and Jennett in 1974, is the standard clinical tool for assessing level of consciousness. It evaluates three behavioral responses: eye opening (E, 1-4), verbal response (V, 1-5), and best motor response (M, 1-6), giving a total score of 3 to 15. A GCS of 15 indicates a fully conscious patient, while a score of 3 represents deepest unconsciousness. GCS is used in trauma triage, TBI assessment, and critical care monitoring. Select the appropriate response for each category below. Scores should always be accompanied by the component breakdown (e.g., E3V4M5 = GCS 12) for clinical communication.
GCS scoring
GCS = E (1-4) + V (1-5) + M (1-6)
Range: 3 (deepest coma) to 15 (fully conscious)
Always document the component scores alongside the total. GCS 8 or below is the traditional definition of coma. Report intubated patients' verbal scores as VT (intubated) rather than excluding them.
GCS severity classification (TBI)
- GCS 13-15: Mild traumatic brain injury.
- GCS 9-12: Moderate traumatic brain injury.
- GCS 3-8: Severe traumatic brain injury. Threshold for intubation consideration.
- GCS 3: Worst score. Absence of all response. May indicate deep coma or brain death (requires further assessment).
Frequently asked questions
What is the Glasgow Coma Scale?
The Glasgow Coma Scale (GCS) is a standardized neurological assessment tool that evaluates a patient's level of consciousness based on three components: eye opening (E, scored 1-4), verbal response (V, scored 1-5), and motor response (M, scored 1-6). The total score ranges from 3 (deepest unconsciousness) to 15 (fully conscious).
How is GCS severity classified?
GCS 13-15: Mild brain injury or normal. GCS 9-12: Moderate brain injury. GCS 3-8: Severe brain injury. A GCS of 8 or below is the traditional threshold for defining coma and is often used as a criterion for endotracheal intubation.
What does each component score?
Eye: 4=spontaneous, 3=to voice, 2=to pain, 1=none. Verbal: 5=oriented, 4=confused, 3=inappropriate words, 2=sounds, 1=none. Motor: 6=obeys commands, 5=localizes pain, 4=withdraws, 3=flexion (decorticate), 2=extension (decerebrate), 1=none. GCS is typically reported as E+V+M (e.g., GCS 15 = E4V5M6).
How is GCS used in trauma care?
GCS is a key component of trauma scoring (Trauma Score, TRISS) and is used to guide triage, airway management, and clinical decision-making. It is assessed on initial evaluation and re-assessed serially to monitor neurological deterioration or improvement.
Are there limitations to the GCS?
GCS cannot be reliably assessed in patients who are intubated (verbal component), heavily sedated, or have facial injuries affecting eye opening. In these cases, the affected component is noted as Not Testable (NT) and the score should be qualified. The pediatric GCS uses modified verbal criteria for young children.
Official sources
- NIH National Institute of Neurological Disorders and Stroke: Traumatic Brain Injury Information.
- Brain Trauma Foundation: Guidelines for Management of Severe TBI.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.