NIH Stroke Scale Calculator
Record all NIHSS component scores, preserve the left/right motor findings, and total the standardized 0–42 scale. The result is a documentation check for trained professionals—not a stroke detector, treatment selector, or reason to wait.
Enter the observed NIHSS item scores
Use the official NINDS booklet, perform items in order, and score what the patient does on the first attempt unless the instructions specifically allow otherwise.
NIHSS documentation result
A total of 6 describes the entered deficits only. Treatment decisions depend on disabling symptoms, onset or last-known-well time, imaging, contraindications, vascular territory, baseline function, and the stroke team’s examination—not this numerical band.
What the NIH Stroke Scale measures
The National Institutes of Health Stroke Scale is a standardized bedside examination used by trained health care professionals to describe neurologic deficit in a person with suspected or confirmed stroke. It samples alertness, orientation questions, simple commands, horizontal gaze, visual fields, facial movement, left and right arm movement, left and right leg movement, limb coordination, sensation, language, articulation, and neglect. Adding the item values produces a score from 0 to 42, where a higher number represents more deficits on this particular examination.
The NIHSS is not a complete neurologic examination. It gives substantial weight to language and anterior-circulation findings. Gait, truncal ataxia, detailed cranial nerve function, subtle hand weakness, swallowing, cognition, and many posterior-circulation findings are not fully represented. That is why a low score cannot clear a patient and why clinicians document the deficit pattern in addition to the total.
This calculator mirrors the numeric ranges in the official NINDS booklet. It intentionally does not ask a visitor to identify a diagnosis or select a treatment. Its role is arithmetic and documentation: preserve each selected component, show useful subtotals, and catch an addition error while the clinician continues the time-critical protocol.
The correct sequence: activate, examine, image, decide
1. Activate
Call the stroke alert, stabilize airway, breathing, circulation, check glucose, and establish last-known-well time. Community users call 911.
2. Examine
Use the official item instructions in order. Avoid coaching and record the first scorable performance where directed.
3. Image
Emergency brain and vascular imaging determines hemorrhage and anatomy. A browser total has no imaging information.
4. Decide
The stroke team integrates time, deficit disability, imaging, medical history, medications, and current protocol.
Scoring should happen inside the emergency workflow, never in front of it. NIH educational material emphasizes that stroke treatment cannot wait. If symptoms began recently, do not drive the patient or spend time repeating an online calculation; emergency medical services can begin coordination en route.
How the 0–42 total is formed
The maximum contributions are 3 for level of consciousness, 2 for questions, 2 for commands, 2 for gaze, 3 for visual fields, 3 for facial palsy, 4 for each arm, 4 for each leg, 2 for ataxia, 2 for sensory loss, 3 for language, 2 for dysarthria, and 2 for extinction or inattention. Their maximum sum is 42.
The displayed subtotals are navigation aids created by this calculator; they are not separate validated scales. The formal clinical record should retain the standard component values and total. If an item is untestable under the official instructions—for example because of amputation, joint fusion, intubation, or another physical barrier—follow the booklet’s specific untestable convention and local electronic record. This browser requires numeric choices, so it is inappropriate when a required component cannot be validly scored.
Several official instructions contain dependencies. A patient scored 3 for item 1a receives specified scores on later items such as language and sensory testing. The calculator does not silently change other selections because doing so could hide an examination inconsistency. The trained examiner must apply all official rules before entering the numbers.
Worked example: why component notation matters
The preloaded demonstration totals 6: one point for answering only one level-of-consciousness question correctly, one for minor facial weakness, one for left-arm drift, one for left-leg drift, one for mild-to-moderate sensory loss, and one for mild-to-moderate aphasia. All other example entries are zero. The same total could arise from a very different pattern, such as a dense isolated deficit in another domain.
Writing only “NIHSS 6” therefore loses clinically useful information. The result strip retains side and domain, helping the user compare the entered examination with the paper form. In clinical documentation, also record examination time, last-known-well time, examiner, changes from baseline, barriers to assessment, glucose, vital signs, and any treatment or transfer actions required by protocol.
The word “mild” in the numerical banner is deliberately qualified. Common descriptive bands vary among references, and a numerically small score can represent a disabling deficit, such as aphasia, hemianopia, or dominant-hand weakness. Never make thrombolysis, thrombectomy, transport, admission, or discharge decisions from an informal severity label.
Item-by-item scoring discipline
| Domain | What the examiner must preserve | Common mistake to avoid |
|---|---|---|
| Consciousness | Use the exact questions and commands in the booklet; aphasia and intubation do not automatically make every item untestable. | Substituting easier questions or accepting approximate answers when exact responses are required. |
| Gaze and vision | Separate voluntary or reflex horizontal eye movement from visual field testing. | Combining gaze preference and hemianopia into one impression. |
| Face and limbs | Test each side, use the specified position and duration, and score drift or effort as defined. | Comparing strength informally without timing the arm and leg holds. |
| Ataxia and sensation | Score ataxia only when out of proportion to weakness and sensory loss only when attributed to stroke. | Scoring weakness itself as limb ataxia or recording chronic neuropathy as acute stroke loss. |
| Language and speech | Distinguish aphasia, a language impairment, from dysarthria, an articulation impairment. | Using slurred speech as proof of aphasia or failing to use the official picture, naming, and sentence material. |
| Neglect | Assess simultaneous stimulation and awareness across modalities as instructed. | Calling a primary sensory or visual deficit neglect without the required evidence. |
What the score cannot tell you
The NIHSS cannot determine whether symptoms are caused by ischemic stroke, intracranial hemorrhage, seizure, migraine, hypoglycemia, intoxication, infection, tumor, functional neurologic disorder, or another condition. Bedside assessment, glucose testing, imaging, laboratory data, history, and specialist judgment establish the differential diagnosis.
It also cannot determine an individual treatment window. Reperfusion eligibility evolves with evidence and depends on much more than elapsed clock time. Some patients are evaluated using advanced imaging and specialized criteria; some have contraindications or mimics; some have a large-vessel occlusion despite a modest score. Follow the current hospital stroke pathway and regional transfer system.
A total is not a prognosis. Age, lesion location and volume, collateral circulation, recanalization, comorbidities, complications, rehabilitation, baseline function, and response to treatment affect outcome. Use validated outcome models only in the populations for which they were developed, and communicate uncertainty compassionately.
Serial scoring and handoff
Repeating the NIHSS at protocol-defined times can reveal improvement, deterioration, hemorrhagic complication, re-occlusion, edema, or a change after treatment. Use the same standardized method. A change in total should lead the clinician back to the components: a two-point rise in language has a different bedside meaning from smaller changes distributed across consciousness and motor function.
During handoff, communicate the total and component pattern, examination time, treatment status, and direction of change. If a component is limited by sedation, intubation, language barrier, preexisting disability, amputation, or poor cooperation, document that context rather than manufacturing a normal score. The calculator does not store a patient timeline and should not be used as the medical record.
Protect privacy. Do not enter names, dates of birth, medical record numbers, or other identifiers into an unapproved website. This tool needs only numeric item choices, and all output should be verified in the authorized clinical system.
Frequently asked questions
Does an NIHSS score of 0 rule out stroke?
No. The scale can miss or underweight clinically important deficits, especially some posterior-circulation findings. Sudden neurologic symptoms still require emergency evaluation.
What NIHSS score is considered severe?
Descriptive bands are commonly used, but cut points vary and do not replace the deficit pattern. This calculator labels ranges cautiously and never uses them to select treatment.
Can a patient or family member use this at home?
No. Use F.A.S.T. warning signs and call 911. Correct NIHSS performance requires training, official stimulus materials, examination technique, and clinical context.
Why are left and right arms and legs separate?
Stroke deficits are often lateralized. Separate scores preserve side and allow the formal total to include each limb exactly as the official scale requires.
Should I change a score after coaching the patient?
Follow the official item instruction. The scale generally emphasizes the observed response without coaching or repeated practice, with item-specific rules controlling what may be repeated.
Can this calculator decide whether tPA or thrombectomy is appropriate?
No. Reperfusion decisions require a stroke team, time history, imaging, contraindication review, disabling-deficit assessment, and current institutional protocol.
Related planning context
For a separate nonclinical U.S. It is unrelated to stroke assessment, medical costs, disability eligibility, or emergency care.
References
- National Institute of Neurological Disorders and Stroke: NIH Stroke Scale booklet
- NINDS: Assess and Treat Stroke
- NINDS: Stroke Signs and Symptoms
- NINDS: Know Stroke—Assessment and Treatment
Professional education and arithmetic support only. Use the official scale and current emergency stroke protocol. If stroke is suspected, call 911.