A 5-year-old has a fever when their temperature reaches 100.4°F (38.0°C) measured rectally, in the ear, or on the forehead, or 100°F (37.8°C) measured by mouth. An armpit reading of 99°F (37.2°C) or higher also counts, though armpit readings are the least accurate method. The number that qualifies as a fever depends entirely on where you take the temperature, so knowing your thermometer type matters.
Fever Thresholds by Thermometer Type
By age 5, most children can hold a digital thermometer under their tongue long enough for a reliable oral reading. That makes oral thermometers a practical everyday option at this age. Here are the cutoffs:
- Oral (mouth): 100°F (37.8°C) or higher
- Rectal, ear, or forehead: 100.4°F (38.0°C) or higher
- Armpit: 99°F (37.2°C) or higher
Armpit temperatures consistently read lower than core body temperature, which is why the threshold is set lower. If an armpit reading seems off or borderline, confirm it with an oral or ear thermometer. For a 5-year-old, oral, ear, and forehead thermometers all provide reasonably accurate readings.
What’s Causing the Fever
The vast majority of fevers in children this age come from viral infections: colds, flu, stomach bugs, and other routine illnesses. These fevers typically range between 101°F and 104°F and last 2 to 3 days. That range can sound alarming, but the height of the fever alone doesn’t tell you how serious the illness is. A child with a 103°F temperature from a common cold can be far less sick than a child with a 101°F fever from a bacterial infection.
Bacterial infections like ear infections, strep throat, or urinary tract infections can also cause fevers. These generally need treatment, which is one reason to pay attention to how long a fever lasts and what other symptoms come with it, not just the number on the thermometer.
How Long a Fever Should Last
A fever from a typical virus resolves within 2 to 3 days. Children’s Hospital Colorado recommends contacting your pediatrician if a fever with other symptoms (cough, runny nose, sore throat) lasts more than 3 days, or if a fever with no other symptoms lasts more than 48 hours. A fever that disappears for a day and then returns also warrants a call.
The 3-day mark is a useful guideline because most common viruses start improving by then. A fever that persists beyond that point raises the possibility of a bacterial infection or a second illness layered on top of the original one.
Keeping Your Child Comfortable
A fever is your child’s immune system fighting an infection, not the illness itself. The goal of managing it at home is comfort, not eliminating the fever entirely.
Hydration is the single most important thing you can do. A feverish child loses fluid faster than normal through sweat and rapid breathing. For a child weighing between 41 and 60 pounds (a typical range for a 5-year-old), aim for at least 10 ounces of fluid per hour, roughly a cup and a quarter. Water, diluted juice, popsicles, and broth all count. If your child is vomiting or has diarrhea alongside the fever, fluid needs go up. Start with small, frequent sips of 1 to 2 tablespoons every 20 minutes and gradually increase.
Dress your child in light clothing and keep the room comfortable. A lukewarm (not cold) bath can help bring temporary relief. Cold water or ice baths can cause shivering, which actually raises core temperature.
Febrile Seizures
Five-year-olds are at the upper edge of the age range for febrile seizures, which are convulsions triggered by a rapid rise in body temperature. These seizures occur most often between 12 and 18 months of age but can happen in children up to age 5. They’re frightening to watch but are typically brief and don’t cause lasting harm. If your child has a seizure with a fever, lay them on their side, don’t put anything in their mouth, and call for emergency help.
Signs That Need Immediate Attention
The fever number matters less than how your child looks and acts. A child who is drinking fluids, responding to you, and playing at least a little between bouts of feeling crummy is generally handling the illness well, even with a temperature of 103°F or 104°F.
Call your pediatrician if your child shows signs of dehydration: no tears when crying, a dry mouth or tongue, sunken eyes, or urinating much less than usual.
Head to an emergency room if your child has a fever along with any of these:
- Extreme drowsiness or difficulty waking up
- A stiff neck
- A new rash, especially one that doesn’t fade when you press on it
- Trouble breathing
- Inconsolable crying
- Difficulty swallowing or excessive drooling
- Stomach pain or tenderness
- Trouble walking or speaking
- Blue or gray color on the lips, tongue, or nails
These symptoms can signal infections like meningitis or sepsis that need treatment fast, regardless of how high or low the fever reads.