Glasgow Coma Scale (GCS) Calculator
Score eye opening, verbal response and best motor response, see the total in standard E V M notation, and get the pupil-adjusted GCS-P.
Standard notation: —
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The Three Components
The Glasgow Coma Scale scores three separate responses and reports them as a sum from 3 to 15. The components are always documented individually, because the same total can describe very different patients:
- Eye opening (E, 1–4) — 4 spontaneous, 3 to sound, 2 to pressure, 1 none
- Verbal response (V, 1–5) — 5 oriented, 4 confused, 3 inappropriate words, 2 incomprehensible sounds, 1 none
- Best motor response (M, 1–6) — 6 obeys commands, 5 localising, 4 normal flexion, 3 abnormal flexion (decorticate), 2 extension (decerebrate), 1 none
Score the best response obtained, use the most noxious stimulus that is clinically appropriate, and record left and right motor responses separately if they differ. The standard shorthand is “GCS 11 (E3 V3 M5)”.
Severity Bands
- 13–15: mild — minor head injury; 13 and 14 still need observation and reassessment
- 9–12: moderate — close monitoring, imaging decisions, frequent re-scoring
- 3–8: severe — coma range; 8 or below is the conventional threshold for considering airway protection
Some classifications place 13 in the moderate band, so the boundaries should be read as conventions rather than absolutes. What matters more than the band is the trend: a fall of two or more points, or any drop in the motor component, is a red flag regardless of the absolute number.
GCS-P: Adding the Pupils
The pupil-adjusted score subtracts a pupillary score from the GCS total: GCS-P = GCS − pupils, where pupils score 0 if both react, 1 if one is absent, and 2 if both are absent. It ranges from 1 to 15 and outperforms the GCS alone for predicting outcome after traumatic brain injury, which is why it has been adopted in several national guidelines. Pupillary status must be assessed and documented with the same care as the three classic components.
Limitations and Pitfalls
- Sedation, paralysis and intubation invalidate parts of the score. Record “V1t” for an intubated patient rather than scoring verbal as 1 without comment.
- Inter-observer variability is real, particularly for the motor component and for distinguishing localising from withdrawal.
- Aphasia, dysarthria, deafness and language barriers distort the verbal component; eye opening may be limited by facial swelling.
- Children under about two years need the paediatric version, with age-appropriate verbal and motor descriptors.
- Alcohol, drugs and metabolic encephalopathy depress the score without structural injury, so the GCS is not a diagnostic test.
- A single value is not enough. The scale was designed for serial assessment by the same observer where possible.
Frequently Asked Questions
What is the lowest possible GCS?
3 — one point for each of the three components. A score of 3 does not mean the patient is brain dead, and a score of 15 does not exclude injury.
How should an intubated patient be scored?
The verbal component cannot be tested. The convention is to record “V1t” and report the score as, for example, “GCS 8 (E2 V1t M5)”, so that nobody mistakes it for a true verbal score of 1.
Why does the motor score carry the most weight?
Because it discriminates outcome better than eye opening or verbal response, and it is the component least affected by factors such as intubation. That is also why a fall in the motor score alone is treated seriously.