Glasgow Coma Scale (GCS) calculator
Score eyes, verbal and motor response, with the breakdown to write in the notes.
What the GCS is for
The Glasgow Coma Scale gives a common language for level of consciousness in head injury, stroke, poisoning, sepsis, hypoglycaemia and any drowsy patient. Its main value is in tracking change: a single number matters less than the trend.
The three components
- Eyes (E1–4): spontaneous 4, to sound 3, to pressure 2, none 1.
- Verbal (V1–5): orientated 5, confused 4, words 3, sounds 2, none 1.
- Motor (M1–6): obeys commands 6, localises 5, normal flexion (withdraws) 4, abnormal flexion 3, extension 2, none 1.
The total ranges from 3 to 15. Score the best response. If there is no response to voice, apply pressure to the fingernail bed (for flexion), the trapezius or the supraorbital notch (for localising). Localising means the hand comes up above the clavicle towards the stimulus.
Interpreting the score
- 13–15: mild
- 9–12: moderate
- 8 or less: severe; the airway is at risk and an anaesthetist is needed
A fall of 2 or more points, or of 1 point in the motor score, needs urgent senior review. In head injury, NICE advises CT within 1 hour if the GCS is below 13 on first assessment or below 15 two hours after the injury.
Worked example
A man found after a road traffic collision opens his eyes only to trapezius pressure (E2), groans (V2) and pulls his arm away from nail-bed pressure (M4). GCS 8 (E2 V2 M4): protect the airway, call anaesthesia and arrange urgent CT.
Pitfalls
- Always write the breakdown, not just the total. E1 V1 M6 and E4 V1 M1 are very different patients.
- Record "NT" (not testable) when a part cannot be assessed: eyes swollen shut, intubation (V written as T), dysphasia or a language barrier.
- Check glucose in every drowsy patient. Hypoglycaemia, opioids and post-ictal states lower the score and are reversible.
- Children under 5 need the paediatric version, which scores age-appropriate verbal responses.
See head injury, reduced consciousness, the drowsy patient and low blood sugar.
Frequently asked questions
What is a normal GCS?
15/15: eyes open spontaneously (4), orientated (5) and obeys commands (6).
What does GCS 8 mean?
Severe impairment of consciousness. Patients with a GCS of 8 or less usually cannot protect their airway and need urgent anaesthetic review.
What is the lowest possible GCS?
3, not 0: one point each for no eye opening, no verbal response and no motor response.
How do I score GCS in an intubated patient?
Score eyes and motor as usual and write the verbal part as T, for example E2 VT M4. Do not add a number for the verbal part.
A calculator supports, but does not replace, clinical judgement. Check results before acting on them.