NIH Stroke Scale (NIHSS) Calculator
The NIH Stroke Scale (NIHSS) is the most widely used quantitative stroke severity assessment. It was developed by the NINDS and is the primary tool used to monitor stroke severity in acute ischaemic stroke care, including thrombolytic and thrombectomy decision-making. The scale comprises 13 examination items (1a, 1b, 1c plus 2–11) scored 0 to 4 (some items 0 to 3 or 0 to 2). The total ranges 0–42. AHA/ASA acute stroke guidelines reference NIHSS thresholds (e.g. ≥ 6 commonly drives consideration of mechanical thrombectomy with appropriate imaging) but exact cutoffs are guideline- and institution-specific.
This tool is for educational and decision-support use only. It does not replace independent clinical judgement. Always verify against the current guideline, FDA label, or specialty reference cited below before acting. Do not enter patient identifiers (name, MRN, dates of service).
Tool
Who this is for
- Emergency physicians and stroke teams
- Neurology residents on the stroke service
- Hospitalists co-managing acute stroke patients
How to interpret the result
| Score / band | Interpretation |
|---|---|
| 0 | No measurable stroke symptoms. |
| 1–4 | Minor stroke. |
| 5–15 | Moderate stroke. |
| 16–20 | Moderate-to-severe stroke. |
| ≥ 21 | Severe stroke. |