What is the normal FEV1 percentage predicted?

• A. ≤60%
• B. 70-80%
• C. ≥80%
• D. >80%

Answer: (D)

FeV1 percentage predicted shows how much air you can forcefully exhale in one second compared with what is expected for your age, sex, height, and ethnicity. A normal result is typically considered when this percent is above about 80% of the predicted value, meaning the lungs are functioning within the expected range. That makes the best answer the one stating a percent predicted greater than 80%. Values at or below 80% suggest some degree of airway limitation, with 70–80% often seen with mild impairment and 60% or lower indicating more significant restriction. For example, if the predicted FEV1 is 4.0 L and the measured FEV1 is about 3.3 L, that’s roughly 82% predicted and would be considered normal.