Glasgow Coma Scale.

What does the Glasgow Coma Scale describe?

The GCS organises observations of eye opening, verbal response and motor response. Its three letters, E, V and M, identify separate findings. The number attached to each letter is a category within that component, rather than a percentage of normal function. The official GCS resource explains the assessment approach.

This calculator uses adult response options. It does not assess a person through the screen: someone must first establish the observed responses. It also does not include pupil reactivity, the GCS-P extension or a paediatric adaptation. Check that the requested instrument matches this page before entering a result.

Components and the calculation

The three components have different maxima. A complete numerical entry produces a total from 3 to 15; 0 is not a GCS total. An unselected field means that an entry is still missing. NT means that a component cannot be tested. These states are deliberately kept separate in the calculator.

Formula: GCS = E + V + M, only when all three components have a numerical score. The displayed denominator is always 15. Do not divide by the number of completed components or add only two values to produce a shortened total.

How to use this calculator

1. Check the adult assessment reference and identify the eye, verbal and motor findings.
2. Select one response in each of the three panels. The selected value appears beside the component and in the result breakdown.
3. If assessment is prevented, use NT for that component. Do not select the lowest numerical option merely to make the calculator display a total.
4. Review the E/V/M breakdown before copying or printing. Use Reset to clear all three entries when starting a new exercise.

A selection can be changed without restarting. The result updates from the current three choices; it does not retain a history of earlier entries. If you are comparing separate observations, keep those records outside this tool in the appropriate documentation system.

Worked examples: totals and non-testable components

These invented examples demonstrate the arithmetic and the tool’s behaviour. They do not describe patients or recommend care.

The first two complete examples both give 12. Their component patterns differ, so a report containing only “GCS 12” would lose information. In the NT example, the tool preserves the eye and motor findings but leaves the total unavailable. A missing motor selection also prevents a total, but its reason is incomplete entry rather than a recorded NT.

How should the total be interpreted?

For traumatic brain injury, NICE describes ranges of 13–15, 9–12 and 3–8 as mild, moderate and severe. The bands shown above refer to that context; they are not general diagnoses for every cause of reduced consciousness.

The interface displays a band to explain the number. It does not determine an individual prognosis, choose treatment or replace the observations behind the total. Compare the named components as well as the sum, and retain any explanation for a component that could not be tested. A result panel is a summary of entered information, not a new examination.

Common entry and reporting mistakes

• Turning NT into 1: this creates a numerical finding that was not established. The official FAQ distinguishes a non-testable component from the lowest response.
• Using a total without E/V/M: different combinations can add to the same result.
• Mixing instruments: this adult page does not supply developmental response criteria for younger children.
• Assuming an old selection was cleared: reset between exercises and check each selected response.

Language or communication barriers, treatment effects and local injuries can complicate assessment. The professional assessment must address those circumstances; this calculator cannot infer which factor applies from a score.

Copying a result and using the PDF resources

Copy result prepares a plain-text summary of the current entries. If clipboard access is unavailable, a text field appears so you can copy manually. Print / save as PDF opens the browser’s print dialogue with a simplified summary. It is a result export, separate from the assessment-aid PDFs linked below.

The export contains no patient identity or observation time. It should not be mistaken for a complete clinical record. The official English and Spanish assessment aids provide a separate reference for the instrument. This page’s explanation and software have not undergone clinical validation or received institutional endorsement.