What is the normal adult respiratory rate range in breaths per minute?

• A. 10-14
• B. 12-20
• C. 20-30
• D. 8-12

Answer: (B)

At rest, the normal adult respiratory rate is about 12 to 20 breaths per minute. This reflects the brainstem’s control of breathing in response to carbon dioxide, oxygen, and blood pH, and it’s a fundamental vital sign used to assess ventilation. Rates below 12 can indicate hypoventilation or central nervous system depression, while rates above 20 suggest tachypnea from fever, hypoxia, anxiety, pain, or metabolic disturbances. Among the options, the 12–20 range best matches the standard resting normal for adults; the other ranges are either too low or too high for a typical resting rate. In practice, slight individual variation exists, but 12–20 is the commonly cited reference.