NIHSS Calculator
Score the severity of an acute stroke with the NIH Stroke Scale (NIHSS). Eleven items — from level of consciousness through motor, sensory, language and inattention — each add points for a total of 0 to 42, where a higher score means a more severe deficit. Choose the finding for each item to get the total and its severity band.
About the NIH Stroke Scale
The NIHSS gives a reproducible measure of stroke severity used through acute care — for treatment decisions, monitoring and communication. Source: Brott T et al., “Measurements of acute cerebral infarction: a clinical examination scale,” Stroke 1989; NIH/NINDS NIH Stroke Scale.
How this is calculated
| Item | Points |
|---|---|
| 1a. Level of consciousness | 0–3 |
| 1b. LOC questions (age, month) | 0–2 |
| 1c. LOC commands (eyes, grip) | 0–2 |
| 2. Best gaze | 0–2 |
| 3. Visual fields | 0–3 |
| 4. Facial palsy | 0–3 |
| 5a. Left arm motor | 0–4 |
| 5b. Right arm motor | 0–4 |
| 6a. Left leg motor | 0–4 |
| 6b. Right leg motor | 0–4 |
| 7. Limb ataxia | 0–2 |
| 8. Sensory | 0–2 |
| 9. Best language | 0–3 |
| 10. Dysarthria | 0–2 |
| 11. Extinction / inattention | 0–2 |
| Maximum | 42 |
Add each item's score for the total. Bands: 0 no stroke symptoms, 1–4 minor, 5–15 moderate, 16–20 moderate to severe, 21–42 severe. Formal use needs NIHSS certification and standard stimulus materials; untestable limbs are excluded per protocol. Source: Brott T et al., “Measurements of acute cerebral infarction: a clinical examination scale,” Stroke 1989; NIH/NINDS NIH Stroke Scale.
Frequently asked questions
What is the NIHSS?
The NIH Stroke Scale is a standardised 15-item neurological examination (grouped into 11 domains) that quantifies the severity of an acute stroke on a 0–42 scale. It is used to describe the deficit, track change over time, help select and monitor treatment such as thrombolysis or thrombectomy, and communicate severity consistently between clinicians. It grew out of a scale developed by Brott and colleagues at the University of Cincinnati in the late 1980s and was later adopted for the pivotal NINDS trial of intravenous tissue plasminogen activator, after which it became the most widely used stroke severity scale in clinical practice and research.
What do the total scores mean?
A common interpretation is: 0 no stroke symptoms, 1–4 minor stroke, 5–15 moderate, 16–20 moderate to severe, and 21–42 severe. Higher scores correlate with larger deficits and, in general, worse outcomes, though the score is read alongside the clinical picture, imaging and time from onset rather than in isolation. A low total does not exclude a significant stroke, since posterior-circulation strokes can cause disabling deficits — such as severe ataxia or an isolated visual field loss — that the scale weighs less heavily than deficits from anterior-circulation strokes.
How are the items scored?
Each item has defined levels: level of consciousness and its questions and commands (items 1a–1c), best gaze, visual fields, facial palsy, motor function of each arm and leg scored 0–4, limb ataxia, sensory loss, best language, dysarthria and extinction/inattention. This calculator lists the standard options for each; the examiner records what the patient actually does, scoring the first attempt. The official instructions specify that each item should reflect what the patient does, not what the examiner believes the patient is capable of, and that a score should not be revised after moving on to a later item.
Are there special scoring rules?
Yes — the full NIHSS has conventions this simplified tool leaves to the examiner: a limb that cannot be tested because of amputation or joint fusion is marked untestable (and not added to the total), ataxia is scored 0 if the limb is too weak to test, and an intubated or language-barrier patient affects the dysarthria and language items. Formal use requires NIHSS certification and the standard stimulus materials. Aphasia itself is not marked untestable — it is captured by the dedicated best-language item, since impaired comprehension or expression is one of the deficits the scale is designed to measure.
What are the limits of the score?
The NIHSS weights left-hemisphere (language) strokes more heavily than right-hemisphere strokes, can under-represent posterior-circulation strokes, and is a snapshot rather than a diagnosis. It supports acute stroke decisions but does not replace imaging or specialist assessment. This calculator is an educational reference, not medical advice.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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