NIH Stroke Scale (NIHSS) Calculator
Calculate the standard adult NIH Stroke Scale from all 15 scored entries, with a 0–42 total, permitted untestable-item documentation, and item-level results.
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About
The NIHSS is a standardized adult 15-item neurological examination scale with a complete numeric total of 0–42. It quantifies observed deficits during one examination to support standardized documentation, communication, and serial assessment. [1, 6]
Use the official NINDS examination materials for the scene, object-naming sheet, sentences, and dysarthria word list required by Items 9 and 10. This calculator records and totals observed item scores; it does not replace the official administration protocol. Official NIH Stroke Scale examination materials [6]
This page follows the formal order and observed-performance principles, but standardized training remains important. NIHSS is not a stroke screening or diagnostic test: a total of 0 does not exclude stroke, and the scale can underrepresent clinically important deficits. This adult standard NIHSS is not modified NIHSS or PedNIHSS and cannot by itself determine thrombolysis or thrombectomy. [2, 5, 9, 10, 11]
Interpretation
What the NIHSS measures
The NIHSS quantifies observed neurological deficits across consciousness, eye movements, visual fields, facial palsy, limb motor function, ataxia, sensation, language, dysarthria, and extinction or inattention. Interpret the total together with all 15 entries: the same total can represent different deficit combinations. [1, 4, 6]
Common descriptive score groups
Administrative and research literature commonly groups complete NIHSS totals as shown below. These are descriptive labels, not official treatment categories, and they must not replace the item pattern or the complete neurological assessment. [8]
| Complete NIHSS total | Common descriptive grouping |
|---|---|
| 0 | No measured NIHSS deficit |
| 1–4 | Minor |
| 5–15 | Moderate |
| 16–20 | Moderate-to-severe |
| 21–42 | Severe |
A score of zero does not exclude stroke
NIHSS 0 does not exclude stroke. A total of 0 means only that no deficit was scored on these NIHSS items during this examination, including when clinically important deficits fall outside or are underrepresented by the scale. [5, 9]
Posterior-circulation, brainstem, cerebellar, gait, some cranial-nerve, and right-hemisphere cognitive, behavioral, or spatial deficits may be underrepresented. [4, 10]
Complete totals and untestable items
A complete 0–42 total is calculated only when all 15 items have numeric scores. UN is permitted only for both arms, both legs, limb ataxia, and dysarthria. For motor arm, motor leg, and limb ataxia, NINDS limits UN to amputation or joint fusion; for dysarthria, UN is limited to intubation or another physical barrier to speech production. UN does not mean uncertain, uncooperative, aphasic, sleepy, or not examined, and it is never scored as 0. [6]
When a permitted item is UN, the page shows only a partial scored-item sum. That partial sum is not a complete NIHSS total; document the untestable item and its reason. [6, 7]
Administration and documentation
Administer items in the formal order, record each observed performance, do not repeatedly coach, and do not go back to revise earlier scores after later information. Record examination time, language and hearing factors, prior deficits, sedation, intubation, and physical barriers; serial examinations should also record factors that affect comparability. [2, 6, 7]
This page does not replace formal training, certification, or a complete neurological examination. [2, 4]
Treatment decisions
The 2026 AHA/ASA acute ischemic stroke guideline emphasizes rapid intravenous thrombolysis for otherwise eligible patients with disabling deficits in the appropriate time window regardless of NIHSS score. A low total may still include disabling aphasia, hemianopia, or function-limiting weakness; a total alone must not be used as a universal thrombolysis gate. [5]
Thrombectomy recommendations depend on specific clinical, anatomic, imaging, timing, and eligibility contexts. This page does not collect vessel occlusion, ASPECTS, infarct-core or perfusion findings, onset time, prestroke function, or treatment contraindications, so it cannot execute an EVT-selection algorithm. [4, 5]
Training and certification
QuickMedCalc does not provide NIHSS certification, and this calculator is not a substitute for standardized training. Use a current official training provider, such as the American Heart Association learning catalog. Open AHA NIH Stroke Scale training. [2, 12]
Related scales and populations
GCS focuses on consciousness level; ABCD² provides a short-term TIA-risk context; mRS and Barthel assess different aspects of function or disability. Modified NIHSS is a different shortened instrument, and PedNIHSS is a distinct pediatric adaptation; neither is calculated here. [4, 5, 11]
References
- Brott T, et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke. 1989;20(7):864–870.
- Lyden P, et al. NIHSS training and certification using a new digital video disk is reliable. Stroke. 2005;36(11):2446–2449. PMID 16224093. DOI 10.1161/01.STR.0000185725.42768.92.
- Lyden P. Using the National Institutes of Health Stroke Scale: A Cautionary Tale. Stroke. 2017;48(2):513–519. PMID 28077454. DOI 10.1161/STROKEAHA.116.015434.
- Scott E Kasner. Clinical interpretation and use of stroke scales. Lancet Neurol. 2006;5(7):603–612. PMID 16781990. DOI 10.1016/S1474-4422(06)70495-1.
- Prabhakaran S, et al. 2026 Guideline for the Early Management of Patients With Acute Ischemic Stroke. PMID 41582814. DOI 10.1161/STR.0000000000000513.
- National Institute of Neurological Disorders and Stroke. NIH Stroke Scale: instructions, scoring definitions, and examination materials. Updated February 2024.
- NINDS. Assess and Treat — NIH Stroke Scale.
- Kogan E, et al. Assessing stroke severity using electronic health record data: a machine learning approach. BMC Med Inform Decis Mak. 2020;20:8. PMID 31914991. DOI 10.1186/s12911-019-1010-x.
- Martin-Schild S, et al. Zero on the NIHSS does not equal the absence of stroke. Ann Emerg Med. 2011;57(1):42–45. PMID 20828876. DOI 10.1016/j.annemergmed.2010.06.564.
- Sato S, et al. Baseline NIH Stroke Scale Score predicting outcome in anterior and posterior circulation strokes. Neurology. 2008. PMID 18434640. DOI 10.1212/01.wnl.0000304346.14354.0b.
- Ichord RN, et al. Interrater reliability of the Pediatric National Institutes of Health Stroke Scale (PedNIHSS) in a multicenter study. Stroke. 2011. PMID 21317270. DOI 10.1161/STROKEAHA.110.607192.
- American Heart Association. ASLS Online and NIH Stroke Scale training catalog. Accessed September 5, 2026.
FAQ
The standard adult NIHSS is an ordinal examination that quantifies neurological deficits observed during one examination across 15 scored entries. It supports documentation, communication, and serial assessment; it is not a stroke screening or diagnostic test and does not itself prove or exclude stroke.
A complete standard NIHSS total ranges from 0 to 42. Administrative and research literature commonly describes 0 as no measured NIHSS deficit, 1–4 as minor, 5–15 as moderate, 16–20 as moderate-to-severe, and 21–42 as severe. These are descriptive groupings, not treatment categories; the item pattern and complete neurological assessment still matter.
Administer items in the formal order, record actual observed performance after each item, do not repeatedly coach, and do not revise earlier scores after later information. The current NINDS NIH Stroke Scale PDF supplies the official scene, object-naming sheet, sentences, and dysarthria word list; this calculator records scores but does not recreate those materials.
UN documents a specific NINDS-permitted limitation, not uncertainty, poor cooperation, aphasia, sleepiness, or an omitted examination. Only both arms, both legs, limb ataxia, and dysarthria allow UN, and a reason is required: for motor arm, motor leg, and limb ataxia the permitted reason is amputation or joint fusion; for dysarthria it is intubation or another physical barrier to speech production. UN is never treated as 0, so this page withholds the complete total and reports only a partial scored-item sum. Intubation can make dysarthria legitimately UN; aphasia does not automatically make dysarthria UN. LOC Questions and the other non-permitted items do not allow UN.
Sources: [6]
Test finger–nose–finger and heel–shin on both sides with the eyes open, and score ataxia only when it is present out of proportion to weakness. Paralysis or inability to understand does not itself count as ataxia. UN is reserved for amputation or joint fusion and requires a documented reason.
Sources: [6]
No. The 2026 AHA/ASA guideline emphasizes rapid intravenous thrombolysis for otherwise eligible patients with disabling deficits in the appropriate time window regardless of NIHSS score. A low total can still include a disabling deficit, and this calculator does not determine treatment eligibility.
Sources: [5]
No. Thrombectomy recommendations depend on specific clinical, vascular, imaging, timing, prestroke-function, and other eligibility criteria. NIHSS thresholds that appear in particular guideline contexts are not universal treatment cutoffs, and this page does not execute an EVT-selection algorithm.
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Disclaimer
Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.