Glasgow Coma Scale (GCS)

Methodology

Glasgow Coma Scale (Teasdale & Jennett 1974; 2014 terminology)

GCS = E (1–4) + V (1–5) + M (1–6) = 3–15

Report the components (e.g. E3 V4 M6) as well as the total; the 'mild/moderate/severe' bands are the traumatic brain injury classification.

Who it is for

Adults and children old enough to speak (use the paediatric version for young children).

Version

1.1.0

How this calculator works

Where the formula comes from

• Teasdale and Jennett published the Glasgow Coma Scale in 1974 as a practical scale to describe impaired consciousness from eye opening, verbal and motor responses.^[1]
• The motor response was later expanded from five to six levels by separating normal from abnormal flexion, giving the 15-point total in use today.^[2]

The inputs

• Eye opening is scored 1–4, verbal response 1–5 and motor response 1–6, so the total ranges from 3 to 15.^[2]
• The 2014 review recommends reporting the three components (for example E3 V4 M6), because different combinations can give the same total.^[2]

Versions and alternatives

• The 2014 terminology uses 'to sound' and 'to pressure' for eye opening and records a component that cannot be assessed as 'not testable' (NT).^[2]
• The GCS-Pupils score (2018) subtracts points for non-reacting pupils, giving a range of 1 to 15.^[3]
• The FOUR score is an alternative coma scale that replaces the verbal response with brainstem reflexes and breathing, so it can be scored in intubated patients.^[4]

Where accuracy falls (published evidence)

• Intubation, sedation, injuries and language or communication barriers may make one or more GCS components untestable or difficult to interpret.^[2]
• A systematic review found reliability was substantial in most good-quality studies, and better with trained assessors.^[5]

What guidelines say

• Traumatic brain injury is commonly classified as mild (13–15), moderate (9–12) or severe (3–8) by the total score.^[2]

Sources

1. Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet. 1974;2(7872):81–84. doi:10.1016/S0140-6736(74)91639-0
2. 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. doi:10.1016/S1474-4422(14)70120-6
3. Brennan PM, Murray GD, Teasdale GM. Simplifying the use of prognostic information in traumatic brain injury. Part 1: The GCS-Pupils score: an extended index of clinical severity. J Neurosurg. 2018;128(6):1612–1620. doi:10.3171/2017.12.JNS172780
4. Wijdicks EF, Bamlet WR, Maramattom BV, Manno EM, McClelland RL. Validation of a new coma scale: the FOUR score. Ann Neurol. 2005;58(4):585–593. doi:10.1002/ana.20611
5. Reith FC, Van den Brande R, Synnot A, Gruen R, Maas AI. The reliability of the Glasgow Coma Scale: a systematic review. Intensive Care Med. 2016;42(1):3–15. doi:10.1007/s00134-015-4124-3

Compiled from the published sources above. Every statement was agreed independently by three AI research tools (Claude, ChatGPT, DeepSeek) and its source verified in PubMed or Crossref by the Hakeemly editorial team. Not reviewed by a doctor unless stated. Agreed on 2026-10-11

Worked example: how to calculate GCS

An illustration with sample values, worked out with the same method the tool above uses.

Limitations

• Intubation, facial injury, sedation and language barriers prevent valid scoring of some components.

References

1. Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet. 1974;2(7872):81–84. doi:10.1016/S0140-6736(74)91639-0
2. 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. doi:10.1016/S1474-4422(14)70120-6