Level of consciousness after head injury. Free to use.
Glasgow Coma Scale (Glasgow Coma Scale (GCS)) is a validated clinical instrument used to assess level of consciousness after head injury. The instrument contains 3 items.
Source / attribution: Teasdale G, Jennett B. Lancet 1974
The instrument's primary construct — level of consciousness after head injury — is operationalized through a fixed set of items, each with a defined response format. This standardisation is what allows Glasgow Coma Scale scores to be compared meaningfully across clinicians, sites, and studies.
Like all screening or assessment instruments, Glasgow Coma Scale is a structured aid — not a diagnostic test in isolation. Results should be interpreted alongside history, examination, and clinical context. Where a score crosses an actionable threshold, the next step is typically a more detailed clinical evaluation rather than a definitive diagnosis.
Answer all 3 items below to see your Glasgow Coma Scale score and interpretation.
Each item is scored on a 4-point scale (1–4). Your score updates live as you answer.
All scoring runs in your browser. No data is sent anywhere — close the tab and the answers are gone.
Glasgow Coma Scale uses simple summation: each item's selected response is converted to a numeric value, and the values are added to produce a total score. Reverse-scored items are inverted before summation.
Scoring notes: Educational use only.
The cutoffs below are drawn from the published validation literature. Always interpret in clinical context.
| Score range | Band | Interpretation |
|---|---|---|
| 3–8 | Severe | Severe. |
| 9–12 | Moderate | Moderate. |
| 13–15 | Mild | Mild. |
This is an illustrative walkthrough, not a real patient. Follow the same four steps with your own answers — or use the live calculator at the top of this page.
Read each question and choose the response that best fits. Each response has a number next to it — that number is the item's score. The example below uses illustrative answers.
| # | Item | Example response | Score |
|---|---|---|---|
| 1 | Eye opening | Spontaneous | 4 |
| 2 | Verbal response | Inappropriate words | 3 |
| 3 | Motor response | Withdrawal from pain | 4 |
Add up all the item scores you noted in Step 1.
4 + 3 + 4 = 11
Find the row in the interpretation table whose range contains your total:
Total = 11 falls between 9 and 12 → Moderate
Moderate. Moderate injury.
A score is one input alongside history and examination. Glasgow Coma Scale supports clinical judgment — it does not replace it.
If Glasgow Coma Scale doesn't fit your context, related instruments in neurology include:
| Scale | Measures | Items | Time |
|---|---|---|---|
| MoCA | Cognitive screening | — | ≈ 10 minutes |
| mRS | Functional outcome after stroke | 1 | — |
| ABCD2 | 2-day stroke risk after TIA | 5 | — |
| NIHSS (Lite) | Stroke severity | 13 | — |
| APGAR Score | Rapid assessment of newborn at 1 and 5 min | 5 | — |
| ASA Physical Status | Pre-operative health status | 1 | — |
| CHA2DS2-VASc | Annual stroke risk in non-valvular atrial fibrillation | 8 | — |
| CURB-65 | 30-day mortality in community-acquired pneumonia | 5 | — |
Glasgow Coma Scale (Glasgow Coma Scale (GCS)) is a validated instrument that assesses level of consciousness after head injury. It is designed for clinicians, medical students, evidence-synthesis researchers. The 3 items are summed to produce a total score.
Glasgow Coma Scale contains 3 items. Item scores are summed to produce the total. Scores run from 3 to 15, grouped into 3 interpretation bands from ‘Severe’ up to ‘Mild’.
On the Glasgow Coma Scale (total score 3–15), scores of 13–15 fall in the ‘Mild’ band — interpreted as: Mild. The full ladder is: 3–8 — Severe: Severe.; 9–12 — Moderate: Moderate.; 13–15 — Mild: Mild. A higher score reflects a more severe presentation, and crossing a cutoff is a prompt to step up assessment or care — but these bands are screening thresholds, not diagnoses.
Scores of 3–8 fall in the ‘Severe’ band: Severe. A low score is reassuring but does not by itself rule out the underlying condition — if symptoms or clinical suspicion persist, reassess over time or use a complementary evaluation rather than relying on the number alone.
Yes — Glasgow Coma Scale is in the public domain and free for clinical, educational, and research use without permission. You can use this calculator and the scale itself freely; if you publish results or reproduce the scale, cite the original source paper.
Teasdale G, Jennett B. Lancet. 1974;2(7872):81-84. This is the original publication for the Glasgow Coma Scale — the reference to cite when reporting results.
No. Glasgow Coma Scale is a structured assessment aid, not a diagnostic test. Its proper role is clinical assessment of level of consciousness after head injury — it standardizes assessment and flags who needs closer evaluation, but the result must be weighed alongside history, examination, and clinical context. When a score conflicts with your clinical impression, clinical judgment takes precedence; treatment decisions should never rest on a screening score alone.
Glasgow Coma Scale is supported by the following peer-reviewed sources: