Glasgow Coma Scale Calculator
Score the Glasgow Coma Scale from eye, verbal, and motor responses.
Get the total GCS score and severity classification from mild TBI to deep coma.
The Glasgow Coma Scale was developed in 1974 at the University of Glasgow by Graham Teasdale and Bryan Jennett. It became one of the most widely used tools in emergency and intensive care medicine because it is fast, reproducible, and does not require special equipment.
The scale has three components: Eye opening (E, 1-4), Verbal response (V, 1-5), and Motor response (M, 1-6). The total GCS score is E + V + M, ranging from 3 (deepest coma) to 15 (fully awake and oriented).
Standard severity classification for traumatic brain injury: Mild TBI: GCS 13-15. The patient is conscious and conversational. This includes most concussions. Moderate TBI: GCS 9-12. The patient can be roused but is not fully oriented. Severe TBI: GCS 3-8. The patient cannot follow commands, open eyes spontaneously, or speak meaningful words. A score of 8 or below defines coma.
The motor score carries the most prognostic weight. An M score of 1 or 2 indicates severe brainstem dysfunction. Decorticate posturing (M3) involves flexion of the arms toward the body; decerebrate posturing (M2) involves extension of all extremities, suggesting damage lower in the brainstem.
The GCS has limitations. It cannot be fully applied to patients who are intubated (V is scored as VT), sedated, or have pre-existing conditions affecting baseline neurological function. In these cases, partial scores like E + M or the full notation with T-suffix are used.
Serial GCS scores matter more than a single reading. A patient falling from GCS 14 to GCS 10 over an hour is a clinical emergency regardless of the absolute number.
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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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