What Temperature Is Considered a Fever?

What temperature is considered a fever - while there are many factors that affect your body temperature, 100.9 F is considered a fever in adults.

Alyssa Corso

Alyssa is a Senior Marketing Associate & Content Writer at Mira. She is passionate about educating others on how to affordably access healthcare.

A fever is an indication your body is fighting off an infection. Everyone’s body runs at a slightly different base temperature, but the average is 98.6 degrees Fahrenheit. A fever is considered any temperature above 100.9F. You should seek medical attention if you are concerned about your fever.

What a Fever Is

A fever is not a disease or a virus. In many cases, a fever indicates your immune system is getting ready to fight off an infection. However, it's important to know that everyone’s body runs at a slightly different base temperature. Still, the average is 98.6 degrees Fahrenheit, and anything above 100.9 F (or 100.4 F for children) constitutes a fever.

Fevers are not inherently bad, even if you feel uncomfortable. In fact, elevated body temperatures help immune cells move quicker.

How to Take Your Temperature

Oftentimes, a fever is accompanied by chills, body aches, sweating, and other symptoms. Along with this, you may want to take your temperature. There are a few ways to take your temperature:

• Oral: This is the most common method when taking your body temperature. In this case, you place a digital thermometer tip under the tongue and wait for an indication such as a beep that your temperature is taken.
• Through the ear: Ear thermometers can provide accurate body temperature results. The device uses infrared rays to read temperatures within the ear canal. Just place the end of the thermometer in the ear canal and wait for the beep.
• Rectal: This is the most accurate way of accessing a body temperature, especially in young children or babies. It involves inserting a Vaseline-covered digital thermometer about half an inch into the anus until the temperature registers. While there are rectal thermometers, regular digital thermometers will work for this method as well.
• Forehead: Forehead thermometers measure the temperature of the temporal artery and have become increasingly popular. However, forehead thermometers are usually more expensive and not quite as accurate compared to other methods.
• Armpit: Taking the body temperature through the armpit is the least accurate method. It can be up to two degrees lower than a rectal temperature.

Normal Body Temperature

A normal body temperature is considered 98.6 degrees Fahrenheit or 37 degrees Celsius. However, this has changed in the past few years.

Studies throughout the years have shown that modern humans actually run closer to 97.5 F.

While this is an average, any given person’s normal temperature can range from 97 to 99 degrees Fahrenheit.

Various factors affect our body temperatures. Some being:

• Strenuous exercise
• Stress
• Smoking
• Meals
• Time of day (body temperature is lowest early in the morning)

It's also important to know that body temperature may vary based on how and where they’re taken. For example, rectal and ear temperatures are higher (and more accurate) than oral and armpit temperatures.

Fever in Children vs. Adults

Body temperatures range in levels. There are four levels: hypothermia, normal, fever or hyperthermia, and hyperpyrexia. These are the considerations when it comes to children and adults.

In Children

In Adults

When to Seek Medical Care with a Fever

You should call your doctor or visit urgent care if your temperature is 103 F (39.4 C) or higher. If you have any of the symptoms below along with a fever, you should seek medical attention:

• Severe headache
• Unusual skin rash, especially if the rash rapidly worsens
• Unusual sensitivity to bright light
• Stiff neck and pain when you bend your head forward
• Mental confusion
• Persistent vomiting
• Difficulty breathing or chest pain
• Abdominal pain or pain when urinating
• Convulsions or seizures

“Breaking” a Fever

When a fever “breaks,” your body is ultimately fighting the infection and calming down.

To break your fever, you can try the following:

1. Stay in bed and rest your body.
2. Stay hydrated. By drinking water, iced tea, or very diluted juice to replenish fluids lost through sweating. You may find it difficult to keep drinks down. In this case, you can suck on ice chips.
3. Reducing the fever helps to break it. Take over-the-counter medications like acetaminophen and ibuprofen to reduce your fever. Be aware of the proper dosage, and be sure not to use it alongside other fever-reducing medications. You also shouldn’t give aspirin to your baby or child without consulting your doctor. Infants under 6 months of age shouldn’t be given ibuprofen.
4. Keep your body cool. Unless you have chills, you should remove extra layers of clothing and blankets so your body can cool off from the fever.
5. Take tepid baths or use cold compresses to make you more comfortable. It's not recommended to take cold baths, ice cube baths, or alcohol baths.

If you have any concerns regarding your fever, be sure to contact your healthcare provider.