About the NIH Stroke Scale Calculator
The National Institutes of Health Stroke Scale (NIHSS) is the standard bedside measure of neurological deficit in acute stroke. First described by Brott and colleagues in Stroke in 1989 and later refined for use in NINDS trials, it scores 15 items covering level of consciousness, gaze, visual fields, facial palsy, motor strength in each arm and leg, limb ataxia, sensation, language, dysarthria and extinction/inattention. Totals range from 0 to 42, with higher scores meaning a more severe deficit.
This calculator is for emergency, stroke and neurology teams, paramedics and students practising for NIHSS certification. Choose the response that matches what the patient does on each item — score what you see, not what you think the patient could do — and the total and a commonly used severity band update instantly. A per-item breakdown helps with handover and repeat examinations.
Items that cannot be tested because of amputation or joint fusion (motor, ataxia) or intubation (dysarthria) are recorded as UN and not added to the total. The NIHSS was developed for adults with acute ischaemic stroke; it under-represents posterior circulation deficits, and a low score does not exclude a disabling stroke. It informs, but does not determine, treatment decisions.
With the default inputs, the nihss total is 13 / 42. Change any value above to recalculate instantly.
How to use the nih stroke scale calculator
- 1Examine items in the listed order and record the first response; do not coach the patient.
- 2Score level of consciousness, LOC questions and commands, then gaze and visual fields.
- 3Grade facial palsy and test each limb separately for drift (arms 10 seconds, legs 5 seconds).
- 4Assess ataxia, sensation, language (picture, naming, sentences), dysarthria and neglect.
- 5Mark UN only for amputation, joint fusion or intubation, and read the total and severity band.
Formula and method
The NIHSS is a simple sum of 15 item scores. Level of consciousness (1a), visual fields, facial palsy and language are scored 0–3; LOC questions, LOC commands, gaze, ataxia, sensory, dysarthria and extinction 0–2; and each of the four limbs 0–4, so motor items alone can contribute up to 16 points. Items recorded as untestable (UN) contribute nothing.
Commonly used severity bands are 0 no stroke symptoms, 1–4 minor, 5–15 moderate, 16–20 moderate to severe and 21–42 severe. These bands are descriptive conventions rather than part of the original scale, and the same total can reflect very different deficits, so the item profile matters as much as the total.
- UN
- Untestable item (amputation, joint fusion or intubation) — scored as 0 and documented
Worked examples
Left-hemisphere stroke with right-sided weakness
LOC questions 1 + gaze 1 + facial palsy 2 + right arm 3 + right leg 2 + sensory 1 + aphasia 2 + dysarthria 1 = 13, a moderate stroke. The motor subtotal is 5 of 16.
Normal examination
Every item scores 0, so the NIHSS total is 0 — no measurable deficit on the scale.
Large stroke with an intubated patient
2 + 2 + 2 + 2 + 2 + 3 + 0 + 4 + 0 + 4 + 0 + 2 + 3 + 2 = 28, with dysarthria untestable because of intubation. A score above 20 falls in the severe band.
Frequently asked questions
What is a normal NIHSS score?+
A score of 0 means no deficit is detected on the scale. Commonly used bands are 1–4 minor, 5–15 moderate, 16–20 moderate to severe and 21–42 severe stroke.
What is the maximum NIHSS score?+
The theoretical maximum is 42. A comatose patient cannot actually reach it, because the official instructions score some items, such as limb ataxia, as 0 when the patient is paralysed or cannot understand the test.
How is ataxia scored if the limb is paralysed?+
Limb ataxia is scored 0 if the patient cannot understand the test or the limb is too weak to perform it. Ataxia is only scored when it is out of proportion to weakness.
Who can perform the NIH Stroke Scale?+
Physicians, nurses, paramedics and therapists can all perform it. Formal NIHSS training and certification is recommended because inter-rater reliability depends on following the standard instructions exactly.
Does a low NIHSS score rule out a serious stroke?+
No. The scale weights anterior circulation and motor deficits, so posterior circulation strokes causing vertigo, gait ataxia or swallowing problems can score low yet be disabling.
For healthcare professionals and education only. This calculator implements a published formula or score but is not a diagnosis and does not replace clinical judgment. Verify inputs and results against the original source before using them in patient care.