NIHSS Calculator (NIH Stroke Scale)
Score the NIH Stroke Scale item by item — consciousness, gaze, visual fields, facial palsy, motor, ataxia, sensory, language, dysarthria and neglect — total 0–42 with stroke severity.
How it works
NIHSS = sum of 15 items: 1a (0–3) + 1b (0–2) + 1c (0–2) + gaze (0–2) + visual (0–3) + face (0–3) + each arm (0–4) + each leg (0–4) + ataxia (0–2) + sensory (0–2) + language (0–3) + dysarthria (0–2) + neglect (0–2); maximum 42. Severity: 0 none · 1–4 minor · 5–15 moderate · 16–20 moderate to severe · 21–42 severe.
The NIH Stroke Scale is the standard bedside measure of neurological deficit in acute stroke, used to grade severity, guide thrombolysis and thrombectomy decisions and track change over time. Items must be scored in order, recording what the patient actually does rather than what the examiner thinks they can do. Items that cannot be tested because of amputation, joint fusion or intubation are marked UN and add no points. Severity bands follow the widely used Brott and NINDS groupings; a higher score means a larger deficit and a worse expected outcome.
Worked example
A patient answers one orientation question correctly (1), has a partial gaze palsy (1), partial lower-face paralysis (2), a left arm that cannot lift against gravity (3), a left leg with some effort against gravity (2), mild sensory loss (1), mild dysarthria (1) and tactile extinction (1): NIHSS = 1 + 1 + 2 + 3 + 2 + 1 + 1 + 1 = 12 / 42 — a moderate stroke.
Sources: Brott T et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke 1989
Frequently asked questions
What NIHSS score is a severe stroke?
Scores of 21–42 are usually called severe and 16–20 moderate to severe. A score of 5–15 is moderate and 1–4 minor. Even a low score can be disabling — isolated aphasia or hemianopia scores only 2–3 points.
How do I score an amputated limb?
Mark the motor or ataxia item as UN (untestable) and write the reason down. UN items add 0 points, so the total understates the deficit — report it alongside the score.
Does the NIHSS decide who gets thrombolysis?
No single score does. Guidelines use the NIHSS together with timing, imaging and whether the deficit is disabling. Thrombectomy trials commonly enrolled patients with an NIHSS of 6 or more, but eligibility depends on the full clinical picture.
Who can perform the NIHSS?
It is designed for physicians, nurses and therapists who have completed NIHSS training and certification, which teaches the exact instructions and scoring rules for each item.
Related calculators
Clinical decision tool for education and for use by trained clinicians alongside clinical judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.