Normal Respiratory Rate for Infants 0-12 Months
The normal respiratory rate for infants aged 0 to 12 months ranges from 20 to 60 breaths per minute, with median values declining from approximately 44 breaths/minute in newborns to 31 breaths/minute by 12 months of age. 1, 2
Age-Specific Normal Values
The respiratory rate in healthy infants shows a predictable decline over the first year of life:
- Newborns (0-2 hours): Median 46 breaths/minute (95th percentile: 65 breaths/minute) 3
- First week to 2 months: Median 42-44 breaths/minute 4, 3, 5
- 0-3 months: 50th percentile approximately 41 breaths/minute 1, 2
- 6 months: Median approximately 35-40 breaths/minute 2
- 12-18 months: 50th percentile approximately 31 breaths/minute 1, 2
The steepest decline occurs during the first two years, with respiratory rate decreasing from a median of 44 breaths/minute at birth to 26 breaths/minute by age 2 years 6.
Critical Thresholds to Recognize
Upper Limit (Tachypnea)
- <2 months old: ≥60 breaths/minute defines tachypnea and warrants evaluation for respiratory distress or infection 1, 7, 2, 4
- 2-12 months old: ≥50 breaths/minute defines tachypnea per WHO criteria 7
Only 2-10% of healthy infants at any age demonstrate rates ≥60 breaths/minute, confirming this as an appropriate threshold for abnormality 4.
Lower Limit (Bradypnea)
- All infants <1 year: <20 breaths/minute is an alarm sign requiring immediate medical attention, as it reflects risk of serious injury or impending respiratory failure 1, 7, 2
Measurement Best Practices
Technique
- Count for a full 60 seconds rather than extrapolating from shorter periods 1, 7, 2, 4. Extrapolation from 15-second counts significantly underestimates the true rate, while 30-second counts show better agreement but still have limitations 4, 5.
- Measure during sleep or when calm and content for the most reliable baseline 2, 4, 3, 5. Respiratory rate is 5.2 breaths/minute higher when awake compared to sleep 3.
- Use a stethoscope placed in front of the nostrils and mouth for optimal accuracy 3, 5. Stethoscope measurements are systematically 1.8-2.6 breaths/minute higher than visual observation alone 5.
Common Pitfalls to Avoid
- Do not measure during crying, irritability, or movement, as this significantly distorts respiratory patterns and makes accurate counting difficult 1, 7, 2
- Avoid brief observation periods—manual measurement requires focused concentration for the full minute and is subject to substantial intra-observer variation 1, 7
- Do not use inappropriate reference ranges, as this leads to misclassification of tachypnea and misdiagnosis of conditions like pneumonia 1, 7
- Recognize high intraindividual variability—even in healthy neonates, respiratory rate can vary by 11.9-34.7 breaths/minute over short time periods, with worsening agreement at higher rates 8
Clinical Context
Factors That Increase Respiratory Rate
- Awake state: Adds approximately 5 breaths/minute compared to sleep 3
- Male sex: Boys have rates approximately 1.6 breaths/minute higher than girls 3
- Heavy meconium staining: Associated with 3.1 breaths/minute increase 3
Factors That Do NOT Significantly Affect Rate
Repeatability
When measured correctly with a stethoscope, respiratory rate shows good repeatability with a standard deviation of differences of only 2.5 breaths/minute in awake infants and 1.7 breaths/minute during sleep 5.