Fever 101: when to call and when to wait

A fever is a symptom, not an illness

A temperature of 100.4°F (38°C) or higher counts as a fever. Most fevers come from common viruses and go away on their own. The number on the thermometer matters less than how your child is acting: a child who is playing between doses of medicine is usually doing fine.

Call right away if

• Your baby is under 3 months old and has any fever.

• The fever is 104°F (40°C) or higher.

• Your child is hard to wake, unusually floppy or can’t be comforted.

• They are working hard to breathe, or have no wet diaper in 8 hours.

• They have a stiff neck, a purple rash that doesn’t fade, or a seizure — call 911.

Comfort at home

• Offer fluids often: water, milk, ice pops.

• Dress them in light layers and keep the room comfortable.

• Use acetaminophen, or ibuprofen if they are over 6 months, dosed by weight. Never give aspirin to children.

Taking a temperature

Under 3 months, a rectal temperature is the most accurate. For older children, an ear or forehead thermometer is fine — just use the same one each time so you can compare.

When to book a visit

Book a same‑day visit if a fever lasts more than 2 days (more than 24 hours in children under 2), keeps coming back, or comes with ear pain, a sore throat or pain when peeing.

This article is general information, not medical advice. If you’re worried about your child, call us — or 911 in an emergency.