Glasgow Coma Scale (GCS) Calculator
Glasgow Coma Scale calculator. Records eye, verbal and motor responses with a not-testable (NT) option, adds them to a 3–15 total when all three can be assessed, and names the head-injury category for that total. Educational only.
Glasgow Coma Scale Calculator
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How to use the Glasgow Coma Scale calculator
Pick a response for each component
Choose one eye, one verbal and one motor response. The labels use the wording the scale's authors adopted in 2014, such as "to pressure" in place of "to pain".
Use NT when a part cannot be assessed
If a component cannot be tested, for example speech in someone who is intubated, choose NT rather than 1. A score of 1 means no response with nothing interfering; NT means the response could not be observed.
Read the components first
The result leads with the three components, written like E3 V4 M5. When all three are scored it adds the 3–15 total, how many of the 120 possible combinations reach that total, and the head-injury category for it. With any NT there is no total.
Treat it as a worked example
The calculator adds up responses you select. It does not observe anyone, so it is a way to learn how the score is built, not an assessment of a person.
The Glasgow Coma Scale is three scores before it is one
Described in 1974, added up from 1979
Graham Teasdale and Bryan Jennett described the scale in Glasgow in 1974 as three separate observations: eye opening, verbal response and motor response. According to the authors' own site, the motor response then had five steps; a sixth, separating normal from abnormal flexion, was added in 1976, giving eye 1 to 4, verbal 1 to 5 and motor 1 to 6. The summed score, 3 to 15, is dated by the authors to a 1979 paper titled "Adding up the Glasgow Coma Score". The 2014 review of the scale's first 40 years reported it in use in more than 80 countries.
The total compresses a lot. Four eye scores, five verbal and six motor make 120 combinations, and they share only 13 totals: a total of 9 can be reached 18 different ways, while only 3 and 15 have a single reading each. The authors' recording guidance gives its own example of a total of 8 that could be E2 V2 M4 or E1 V1 M6, "with very different implications". That is why the 2014 review says individual patients are best described by the three components, while the total "should be used to characterise groups".
"The same total can describe very different responses, which is why the scale is written as its three parts."
Mild, moderate and severe are head-injury categories
The bands 13 to 15, 9 to 12 and 3 to 8 come from head-injury research and guidance, not from the 1974 scale. Rimel and colleagues (Neurosurgery, 1982) divided head injury into "severe, 3-8; moderate, 9-12; and minor, 13-15", and NICE's head-injury guideline NG232 (2023) defines mild, moderate and severe traumatic brain injury by the same ranges. They classify injuries across groups of patients. This calculator shows the category for a total so the convention is visible, not as a judgement about one person.
When a part cannot be tested
Eyes swollen shut, a breathing tube, or paralysis can make a component impossible to observe. The authors' answer is to write NT (not testable) for that component, never 1, and not to report a total at all, because the low number would make the person look more unwell than they are. They add that a missing component can be estimated statistically, but call that probably more relevant to research than clinical practice. This calculator follows the first rule: choose NT and it shows the components, for example E3 VNT M5, with no total and no category.
The lowest possible score is 3, and the components matter more than the total
Described in 1974 by Teasdale and Jennett; the summed score dates from a 1979 paper.
Eye (1–4) + Verbal (1–5) + Motor (1–6) = 3 to 15.
The lowest possible score is 3, not 0: every component starts at 1.
The motor scale gained its sixth step, normal versus abnormal flexion, in 1976.
E, V and M combine in 120 ways but reach only 13 different totals.
Individual patients are best described by the components, e.g. E3 V4 M5 (2014 review).
13–15 / 9–12 / 3–8 are head-injury categories (Rimel 1982; NICE NG232).
A component that cannot be assessed is written NT, and no total is reported.
In 2014 "inappropriate words" and "incomprehensible sounds" became "words" and "sounds".
In use in more than 80 countries, per the 2014 review.
Frequently asked questions
It is a standardised way to describe a person's level of consciousness through three observed responses: eye opening (1–4), verbal response (1–5) and motor response (1–6). Teasdale and Jennett described it in 1974; the summed 3–15 score came later, in 1979, according to the scale's authors.
Each of the three components has a minimum score of 1, which means no response, so the lowest possible total is 1 + 1 + 1 = 3. There is no zero.
From head-injury research and guidance, not the original scale. Rimel et al. (Neurosurgery, 1982) divided head injury into severe (3–8), moderate (9–12) and minor (13–15), and NICE's head-injury guideline NG232 (2023) defines mild, moderate and severe traumatic brain injury by the same ranges. They are categories for groups of head injuries; the calculator shows them for reference and does not use them to describe a person.
Because one total can be reached in many ways. A total of 10 can be E4 V1 M5 or E2 V4 M4, and the calculator counts 17 combinations that reach 10. The 2014 review of the scale says individual patients are best described by the three components, and the total should be used to characterise groups.
Not testable. When a component cannot be assessed, for example speech in someone who is intubated, the scale's authors say to record it as NT rather than as 1, and not to report a total score, because the low number could make the person seem more unwell than they are. The reading is written as its components, such as E3 VNT M5. This calculator follows that rule: with any NT it shows no total and no category.
Because change over time carries information a single reading does not. NICE's head-injury guideline (NG232, recommendation 1.9.13, first made in 2003) lists among signs of deterioration a sustained drop of 1 point in the score (for at least 30 minutes), any drop of 3 or more points in the eye or verbal score, or 2 or more points in the motor score. This calculator scores one set of responses and does not track a series.
A component may be impossible to assess because of intubation, sedation, paralysis, swelling around the eyes or a language barrier, which is what NT records. The total also hides which component produced it. Consistency between observers depends on using the same graded stimulus, which is why the authors publish a structured assessment aid.
No. The scale is designed for trained assessors using a standardised technique, and this calculator does not assess anyone: it adds up the responses you select. It is an educational aid, not a substitute for emergency care.
Several exist. The scale's authors say the adult scale can be applied without modification to children over 5 years old. For younger children they describe a paediatric scale from Adelaide with age-appropriate verbal responses and a five-step motor column, so its maximum is 14 rather than 15, and they note that although several other systems have been put forward, none has gained wider acceptance. NICE's guideline uses its own paediatric version with a "grimace" alternative for preverbal children. This calculator uses the adult scale only.
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.
Method & sources
How it computes
Glasgow Coma Scale = Eye (1–4) + Verbal (1–5) + Motor (1–6), total 3–15, reported only when all three components can be assessed: any component recorded NT (not testable) gives the components and no total, per the scale's authors. The total is shown with how many of the 120 combinations reach it and its head-injury category, 13–15 / 9–12 / 3–8 (Rimel et al. 1982; NICE NG232).
What this tool implements
- Component scales eye 1–4, verbal 1–5, motor 1–6: described by Teasdale and Jennett in 1974 with a five-step motor response; the sixth step was added in 1976 and the summed 3–15 score dates from 1979, per the scale's authors.
- A component that cannot be assessed is recorded NT, never 1, and no total is reported when any component is NT (the authors' FAQ). The calculator then shows the components only, e.g. E3 VNT M5.
- Categories 13–15 / 9–12 / 3–8 are head-injury categories (Rimel et al. 1982; NICE NG232 mild, moderate and severe traumatic brain injury). They are shown for reference, without clinical instruction, and not as a verdict on one reading; individuals are described by the components.
- Component wording follows the authors' 2014 structured approach: "to pressure", "words", "sounds", "localising" (Teasdale et al., Nursing Times 2014).
- Educational aid gated behind a medical acknowledgement; it adds up selected responses and does not assess a person.
Sources
- Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet 1974;2(7872):81-84. PMID 4136544. doi:10.1016/S0140-6736(74)91639-0
- Teasdale G, Jennett B. Assessment and prognosis of coma after head injury. Acta Neurochir (Wien) 1976;34(1-4):45-55. PMID 961490.
- Teasdale G, Maas A, Lecky F, Manley G, Stocchetti N, Murray G. The Glasgow Coma Scale at 40 years: standing the test of time. Lancet Neurol 2014;13(8):844-854. PMID 25030516. doi:10.1016/S1474-4422(14)70120-6
- Rimel RW, Giordani B, Barth JT, Jane JA. Moderate head injury: completing the clinical spectrum of brain trauma. Neurosurgery 1982;11(3):344-351. PMID 7133350.
- National Institute for Health and Care Excellence. Head injury: assessment and early management (NG232), 2023. https://www.nice.org.uk/guidance/ng232/chapter/Recommendations
- Glasgow Coma Scale, the scale's authors: history and sum score https://www.glasgowcomascale.org/what-is-gcs/ ; NT and children https://www.glasgowcomascale.org/faq/ ; 2014 wording https://www.glasgowcomascale.org/gcs-aid/
What can make this go out of date
- none at runtime
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