Glasgow Coma Scale Calculator
Score a patient's level of consciousness using the Glasgow Coma Scale (GCS). Used by clinicians to assess eye, verbal, and motor responses after head injury or altered mental status.
About this calculator
The Glasgow Coma Scale quantifies consciousness by scoring three independent neurological responses: eye opening (E, scored 1–4), verbal response (V, scored 1–5), and motor response (M, scored 1–6). The total GCS score is simply GCS = E + V + M, ranging from 3 (deep coma or death) to 15 (fully conscious). A score of 13–15 indicates mild brain injury, 9–12 moderate injury, and 3–8 severe injury requiring urgent intervention. The scale was developed at the University of Glasgow in 1974 and remains the international standard for rapid, reproducible neurological assessment. It is used in emergency rooms, ICUs, and trauma settings to track changes in consciousness over time and to guide treatment decisions including intubation thresholds.
How to use
Consider a trauma patient who opens eyes only to pain (E = 2), makes incomprehensible sounds but no words (V = 2), and withdraws from painful stimulus (M = 4). Step 1: E = 2. Step 2: V = 2. Step 3: M = 4. Step 4: GCS = 2 + 2 + 4 = 8. A GCS of 8 indicates severe brain injury. Clinical guidelines typically recommend securing the airway (intubation) for patients with GCS ≤ 8, so this score would prompt immediate airway management.
Frequently asked questions
What does a Glasgow Coma Scale score of 3 versus 15 mean clinically?
A GCS of 15 is the maximum score and indicates a fully alert, oriented patient who opens eyes spontaneously, speaks normally, and follows commands. A GCS of 3 is the minimum possible score, representing no eye opening, no verbal response, and no motor response — consistent with deep coma or brain death. The difference between these extremes guides entirely different clinical interventions. Scores ≤ 8 generally trigger consideration of intubation to protect the airway, while scores of 13–15 may allow conservative monitoring.
How is the Glasgow Coma Scale used to classify traumatic brain injury severity?
Clinicians use the GCS recorded within the first 24 hours to classify TBI as mild (GCS 13–15), moderate (GCS 9–12), or severe (GCS 3–8). Mild TBI corresponds to concussion and usually requires only observation. Moderate TBI often warrants CT imaging and hospital admission. Severe TBI is a medical emergency associated with high mortality and long-term disability risk. Serial GCS measurements are equally important — a falling score signals deterioration and may indicate expanding intracranial hemorrhage requiring neurosurgical intervention.
Can the Glasgow Coma Scale be used in non-verbal or intubated patients?
Intubated patients cannot produce a verbal response, so their verbal score is typically recorded as 1T (T for tube) and the GCS is reported as a combined eye + motor score out of 10. Pediatric patients under 2 years also require a modified scale because age-appropriate responses differ — for example, a crying infant scores differently than a non-verbal toddler. Some clinicians prefer the motor score alone (M score, 1–6) as a reliable predictor in intubated patients. The GCS should always be interpreted alongside other clinical findings, not in isolation.