Neck Disability Index Calculator

About this calculator

The Neck Disability Index (NDI) is a patient-reported outcome questionnaire — ten sections covering pain intensity, personal care, lifting, reading, headaches, concentration, work, driving, sleeping, and recreation — with each section scored 0 (no disability) to 5 (worst disability). The raw section scores are summed and converted to a percentage: NDI % = (total raw score) / (5 × number of sections answered) × 100, which normalizes the score whether all ten sections were completed or a section was skipped as not applicable.

The resulting percentage sorts patients into standard disability categories — commonly no disability, mild, moderate, severe, and complete disability — that clinicians use to track a patient’s progress over the course of treatment for neck pain, whiplash, or cervical spine conditions. Physical therapists, chiropractors, and orthopedic clinicians administer the NDI at intake and at follow-up visits to quantify functional impairment and measure whether treatment is producing a meaningful change; this calculator converts a raw total score and the number of sections answered into the NDI percentage and its disability category.