Glasgow Coma Scale Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/9/2026
The Glasgow Coma Scale adds up three sub-scores: eye opening (1 to 4), verbal response (1 to 5), and motor response (1 to 6), for a total from 3 (no response) to 15 (fully conscious). A score of 15 (4+5+6) corresponds to a fully conscious, oriented person.
Explanation
The Glasgow Coma Scale (GCS), developed by Teasdale and Jennett in 1974, is the reference tool for assessing and tracking a person's level of consciousness, particularly after a head injury. It rests on three independent components, each scored separately and then added together: eye opening (from 4, spontaneous, to 1, no opening even to pain), verbal response (from 5, oriented in time and place, to 1, no sound), and motor response (from 6, obeys simple commands, to 1, no movement even to a painful stimulus) — this last component is generally considered the most predictive of neurological outcome among the three. The total score, ranging from 3 (the minimum possible, never 0) to 15 (the maximum, normal neurological function), allows a usual classification into three severity categories: a score of 13 to 15 corresponds to mild head injury, a score of 9 to 12 to moderate injury, and a score of 8 or below to severe injury, this last threshold classically associated with the need for airway management. This score's main value lies as much in its absolute value at a given moment as in how it changes over time: a drop in score in the same patient, even without crossing a category threshold, is a neurological warning sign to take seriously. This score remains a standardized clinical tool for healthcare professionals to objectively assess and communicate a level of consciousness, never a self-assessment tool or a substitute for emergency medical care in a real head injury — alongside other vital signs like the shock index or blood pressure, it forms part of the broader picture used to judge how urgent a situation is.
Example: E3, V4, M5 (a score of 12)
Inputs
Eye opening: 3 (to verbal command). Verbal response: 4 (confused). Motor response: 5 (localizes pain).
Calculation
Total score = 3 + 4 + 5 = 12.
Result
This score of 12 corresponds to moderate head injury (9 to 12).
Frequently asked questions
Why is the minimum score 3 and not 0?
Because each of the three components has a minimum value of 1 point, never 0, even with a complete absence of observable response: the minimum total score is therefore 1+1+1=3, not 0. A score of 0 doesn't exist on this scale, which sometimes confuses people encountering the tool for the first time.
Which component of the score is clinically most important?
The motor response is generally considered the most predictive component of neurological outcome among the three, especially when the verbal response can't be assessed (an intubated patient, for example). Some clinical protocols in fact use the motor score alone as a simplified alternative in this specific context.
Can this score be calculated for an intubated patient who can't speak?
The verbal component can't be assessed normally in an intubated patient, which is generally noted separately (often with a "T" for intubated) rather than replaced by an arbitrary estimate. This calculator assumes a standard assessment of all three components; in real clinical practice with an intubated patient, interpreting the score requires the expertise of a healthcare professional trained for this specific situation.