Glasgow Coma Scale (GCS) Calculator
Score a level of consciousness with the Glasgow Coma Scale (GCS), the standard bedside measure of impaired consciousness after head injury and in other acute illness. It adds three responses — eye opening, verbal response and motor response — for a total from 3 (deep unconsciousness) to 15 (fully alert). Choose the best response in each category to get the total and the severity band.
About the Glasgow Coma Scale
The GCS gives a reproducible measure of consciousness by scoring the best eye, verbal and motor responses, totalling 3–15. Source: Teasdale G, Jennett B, “Assessment of coma and impaired consciousness: a practical scale,” The Lancet 1974;304(7872):81–84.
Frequently asked questions
How is the GCS scored?
The GCS adds three components. Eye opening scores 4 (spontaneous), 3 (to speech), 2 (to pain) or 1 (none). Verbal response scores 5 (oriented), 4 (confused), 3 (inappropriate words), 2 (incomprehensible sounds) or 1 (none). Motor response scores 6 (obeys commands), 5 (localises pain), 4 (withdraws from pain), 3 (abnormal flexion), 2 (extension) or 1 (none). The best response in each category is used, giving a total of 3 to 15.
What is a mild, moderate or severe GCS?
By convention a total of 13–15 is mild, 9–12 is moderate, and 8 or below is severe — the last often described as coma. A GCS of 8 or less is a common threshold for considering airway protection. The trend over time matters as much as any single value: a falling GCS is an important warning sign.
How do I record the score?
Best practice is to report the three GCS parts as well as the total, for example “GCS 10 (E2 V4 M4)”, because the same total can reflect different patterns. If a component cannot be tested — for instance a verbal score in an intubated patient — it is noted as not testable (often written “T”) rather than guessed. This calculator prints the breakdown as E, V and M beside the total for exactly that reason. Recording the components also lets the next assessor see which part changed when the total moves.
When is the score less reliable?
Sedation, intoxication, paralysis, intubation, language barriers, dementia and pre-existing deficits can all distort the GCS. In intubated patients the verbal component cannot be assessed. It is a measure of consciousness, not a diagnosis, and should always be interpreted alongside the wider clinical picture.
Who developed the Glasgow Coma Scale?
The Glasgow Coma Scale was introduced by Graham Teasdale and Bryan Jennett in Glasgow in 1974 to give a reproducible way to describe consciousness. It is now used worldwide in emergency, trauma, neurosurgical and intensive-care settings. This calculator is an educational reference, not medical advice.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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