This is general guidance, not a substitute for medical advice. Trust your instincts: how your child looks and behaves often matters more than the exact number. When in doubt, call your pediatrician or nurse line.
What temperature counts as a fever?
A fever is generally a temperature of 100.4°F (38°C) or higher. The most accurate method varies by age, and a forehead or ear thermometer is convenient for children. See our fever guide for measurement methods and our accurate temperature guide for technique.Why does age matter so much with fever?
The younger the child, the lower the threshold for concern:- Under 3 months: any rectal temperature of 100.4°F (38°C) or higher is a reason to call the doctor right away, even if the baby seems well.
- 3–6 months: call for a fever, especially if the baby is fussy, lethargic, or feeding poorly.
- Older infants and children: the number matters less than how they look and act.
When should I call the doctor or seek urgent care?
Contact your pediatrician promptly, or seek urgent care, if your child has:- A fever in a baby under 3 months (see above)
- A fever above 104°F (40°C), or one that won’t come down
- A fever lasting more than a few days
- A stiff neck, severe headache, trouble breathing, a rash that doesn’t fade with pressure, or a seizure
- Signs of dehydration, unusual drowsiness, or difficulty waking