Glasgow Coma Scale (GCS) Calculator
Glasgow Coma Scale calculator. Sums eye, verbal and motor responses to a 3–15 total with a mild / moderate / severe consciousness band. Educational only.
Glasgow Coma Scale Calculator
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How to use the Glasgow Coma Scale calculator
Score each response
Choose the best eye-opening, verbal, and motor response observed. Always score the best response on the better side of the body for motor.
Use a standardised stimulus
Apply a graded stimulus — first sound, then pressure — consistently, so the assessment is reproducible between observers and over time.
Acknowledge, then read the total and components
The total runs from 3 to 15 and maps to a mild, moderate, or severe band. Crucially, record the breakdown — for example E3V4M5 — not just the number.
Track the trend
A single GCS matters less than its change. A falling score signals deterioration and is a medical emergency. Repeat assessment and clinical judgement guide management.
The Glasgow Coma Scale — a common language for consciousness
Three responses, one shared scale
Before 1974, describing a patient's level of consciousness relied on vague, inconsistent terms — "drowsy", "stuporous", "semi-comatose" — that meant different things to different clinicians. Graham Teasdale and Bryan Jennett, working in Glasgow, replaced that ambiguity with a structured scale that assesses three independent responses: eye opening (scored 1 to 4), verbal response (1 to 5), and motor response (1 to 6). Adding them gives a total from 3, the deepest unresponsiveness, to 15, fully alert. The genius of the scale is that it is reproducible: two clinicians assessing the same patient should arrive at nearly the same components, which lets a finding recorded in an ambulance be compared meaningfully with one taken hours later in a ward. It became, and remains, the universal language for describing impaired consciousness in trauma, stroke, poisoning, and critical illness worldwide.
By convention, totals of 13 to 15 indicate mild impairment, 9 to 12 moderate, and 8 or below severe — the last being the traditional threshold at which the airway is at risk and intubation is considered, because a patient who cannot protect their airway can aspirate. But the total is only a summary. Two patients can both score 10 yet be clinically very different, which is why the scale is always reported as its three parts, such as E3V4M5, not as a bare number.
"The same total can hide very different patients — that's why the Glasgow Coma Scale is always recorded as its three components, and why a falling score matters more than any single reading."
Reading it well — and its limits
The motor score carries the most prognostic weight and is the part clinicians watch most closely; a deteriorating motor response is an ominous sign. The scale does have practical limitations: it can't be fully assessed in patients who are intubated (the verbal component is recorded as non-testable, often written "VT"), heavily sedated, paralysed, or unable to cooperate because of language or intoxication, and these factors must be documented so the score isn't misread. Eye swelling can prevent eye-opening assessment too. None of this undermines the scale; it just means the components and the context have to be recorded honestly. Above all, the GCS is a tool for trained assessors using a standardised technique, and its real value lies in trend — a single number is a snapshot, but a series tells the story. A drop in GCS is a clinical emergency requiring immediate medical attention. This calculator is an educational aid for understanding how the score is built; it is not a way to assess a real patient, which requires hands-on examination by a clinician.
10 Facts About the Glasgow Coma Scale
Introduced in 1974 by Teasdale and Jennett.
Eye (1–4) + Verbal (1–5) + Motor (1–6) = 3 to 15.
The lowest possible score is 3, not 0.
13–15 mild, 9–12 moderate, ≤8 severe.
GCS ≤8 is the traditional airway-protection threshold.
Always report the components (e.g. E3V4M5), not just the total.
The motor score carries the most prognostic weight.
Intubated patients: verbal is non-testable ("VT").
The trend matters more than any single reading.
It's the universal language for impaired consciousness.
Frequently asked questions
It is a standardised way to describe a person's level of consciousness, assessing three responses — eye opening (1–4), verbal (1–5), and motor (1–6) — and summing them to a total from 3 to 15. Introduced in 1974, it gives clinicians a reproducible, shared language to record and compare consciousness over time in trauma, stroke, poisoning, and critical illness.
Each of the three components has a minimum score of 1, even when there is no response at all, so the lowest possible total is 1 + 1 + 1 = 3. There is no zero. A score of 3 represents the deepest unresponsiveness — no eye opening, no sounds, and no movement to stimulus.
By convention, 13–15 indicates mild impairment of consciousness, 9–12 moderate, and 8 or below severe. In traumatic brain injury these bands correspond loosely to mild, moderate, and severe injury. A score of 8 or less is the traditional threshold for considering airway protection, because such patients may not be able to keep their airway safe.
Because the same total can describe very different patients. A GCS of 10 made up of E4V1M5 is not the same clinically as E2V4M4, even though both add to 10. Recording the breakdown — for example E3V4M5 — preserves that information, and because the motor component is the most prognostically important, seeing it explicitly matters. Best practice is to document all three parts every time.
An intubated patient can't speak, so the verbal component is recorded as non-testable, conventionally written as "VT" (or "T" appended to the score, e.g. E3VTM5). The eye and motor components are still assessed normally. This avoids falsely assigning a verbal score of 1, which would understate the patient's true level of consciousness. Sedation and paralysis must also be documented for the same reason.
The trend is more informative than any single value. A dropping GCS — especially a falling motor score — signals worsening brain function, which in a head injury may mean a rising intracranial pressure or an expanding bleed. A drop of two or more points is a recognised trigger for urgent reassessment, imaging, and possibly neurosurgical input. That is why GCS is monitored repeatedly rather than recorded once.
It can be hard or impossible to apply fully in patients who are intubated, sedated, paralysed, intoxicated, or unable to cooperate because of a language barrier, and facial swelling can prevent eye-opening assessment. Inter-rater reliability also depends on using a standardised stimulus technique. None of these invalidate the scale, but they must be documented so the score is interpreted correctly rather than taken at face value.
No. The GCS is a tool for trained assessors using a standardised technique, and a genuinely reduced level of consciousness is a medical emergency. If someone is drowsy, confused, not waking properly, or deteriorating after a head injury, call emergency services immediately rather than trying to score them. This calculator is educational, to explain how the scale works — not a substitute for emergency care.
Yes. Because infants and young children can't follow verbal commands or speak as adults do, a modified Paediatric Glasgow Coma Scale adapts the verbal and motor descriptors to age-appropriate behaviours (such as crying, grimacing, and spontaneous movement). The structure and scoring range are the same. This calculator uses the standard adult scale, so it isn't appropriate for assessing young children.
No. The responses you select are processed only in your browser. Nothing is sent to a server, stored, or shared, and no account is required. The calculation runs entirely on your device.
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