What Is a Normal Body Temperature?
Medically reviewed by Michael Menna, DO
The human body's normal temperature was long considered to be 98.6 degrees Fahrenheit. Normal adult body temperatures actually range from 97 to 99 F. Plus, there's some evidence to suggest normal temperature has decreased over time and is closer to 97.9 F.
Your temperature can fluctuate and vary based on your age and the method used to measure your temperature. A fever is when your body temperature is higher than normal. Most healthcare providers consider a fever to be at 100.4 or higher.
This article reviews normal human body temperature and fever based on age, how it varies with measurement methods, symptoms, at-home fever treatment, and when to call a healthcare provider.
Illustration by Michela Buttignol for Verywell Health
Is 98.6 Degrees a Normal Temperature?
The average human body temperature is 98.6. However, this is just an average and varies among people. Several factors can affect body temperature, including age, sex, and where on your body you take it.
Your baseline daily temperature is a good reference point, and everyone's unique. For example, your daily average temperature could be around 97 degrees while your friend's average temperature is 98.7. Across a person's lifespan, healthy, normal body temperature ranges in degrees Fahrenheit from 96 to 99.9.
Infants and Children
A baby or child’s normal temperature varies based on age as follows:
Preterm newborns: 97.7–98.6 F
Term newborns: 97.2–99.9 F
Babies less than 6 months old: 97.2–99.4 F
6–12 months: 96–99.7 F
1–13 years: 95.9–99 F
Adults
The normal body temperature range for teens and adults is 97–99 F. People over age 60 have slightly lower temperatures than those younger than 60.
Average Temperature by Method
Body temperature differs based on where on your body you take your temperature.
Central temperature measurement sites include the rectum (anus), which is a more invasive site typically used for young infants or people who are severely ill. Urine may be close to your core temperature when using an internal Foley catheter with a sensor, for example. But method matters, and excreted urine is cooler when measured outside the body.
Peripheral sites include oral (mouth), axillary (armpit), or tympanic (ear). Environmental temperature can influence these areas, so they are slightly less accurate than central sites. However, they are more accessible and practical for daily use.
Oral
Oral temperatures are taken in the mouth. The room temperature, hot or cold liquids, and probe placement can influence oral temperatures. One study showed a variation of 3.6 degrees between oral and rectal temperatures. Normal and average oral temperatures are as follows:
Normal range: 96.3–99.3 F
Average: 97.8 F
Tympanic
Tympanic (ear) thermometers are fast and easy to use. They can vary a couple of degrees between ears and in comparison to a rectal temperature. These are normal and average tympanic temperatures:
Normal range: 96.4–99.5 F
Average: 97.9 F
Axillary
Axillary temperatures are taken under the arm. They are affected by the external environment and vary from rectal temperatures. Normal and average axillary temperatures are as follows:
Normal range: 95.1–98.4 F
Average: 96.7 F
Rectal
Rectal (in the anus) temperature most accurately measures the core temperature. It is typically about 1 degree higher than oral readings. Healthcare providers commonly use rectal temperature measurements for babies less than 3 months old. These are the normal and average rectal temperatures:
Normal range: 97.3–99.9 F
Average: 98.6 F
Fever During Pregnancy
It’s normal to have a slightly elevated temperature during pregnancy. But, you should report a fever (temperature over 100.4 degrees) to your healthcare provider. A fever could indicate an illness such as the flu or COVID-19. Your healthcare provider may want to order tests, prescribe medications, or monitor you carefully.
Related: The 8 Best Thermometers for At-Home Use, Tested and Reviewed
What’s Considered a Fever?
A fever occurs when your body temperature is higher than normal and is usually a response to a disease or illness. Fevers are graded as mild, high, and very high as follows:
Elevated body temperature: 99.5–100.4 F
Low-grade fever: 100.4 F or higher
High-grade fever: 103 F
Very high or dangerous: Above 105 F
The following is how a fever is defined in children based on where the temperature is taken:
Rectal: Above 100.4 F
Oral: Above 99.5 F
Axillary: Above 99 F
Guidelines for seeking medical attention, based on age, are we follows:
3 months or younger: Rectal temperature over 100.4 F
3–12 months: 102.2 F or higher
12 months to 2 years: 103 F or higher, despite treatment or any fever that lasts longer than 24–48 hours
2 years and older: 103 F or higher, despite treatment or any fever lasting longer than 48–72 hours
The following guidelines for seeking medical attention for a fever apply to any age, including adults:
An elevated temperature that comes and goes for a week or more, even if it’s not considered a fever
Other symptoms of illness, along with the fever
People with any grade of fever who have had an organ transplant or a serious medical illness
Those who have recently traveled to another country
Low Body Temperatures
While people often are concerned with elevated temperatures and fevers, it’s important to note that low body temperatures could signify a health condition as well, especially in infants.
A low body temperature in young infants could indicate a serious illness called sepsis. A rectal temperature is the most accurate for infants younger than 3 months old.
When Is a Fever Considered a Medical Emergency?
In children ages 1 year or older, seek emergency medical attention for a fever rising above 103 degrees despite treatment. Getting medical attention before temperatures reach 105 degrees is crucial because it becomes more dangerous after 105. Treating temperatures before they reach 105 typically leads to better outcomes.
Related: What Causes a Low Temperature?
Symptoms of Fever
Symptoms of a fever can be constant or intermittent (come and go). They include:
Feeling warm or hot
Skin warm to touch
Flushed face
Chills
If the following symptoms occur along with a fever, they could indicate an underlying health problem that requires medical attention:
Malaise (generally feeling unwell), especially if occurring with a fever
Decreased urine output or dark urine
Persistent nausea or vomiting
Persistent constipation or diarrhea
Headache
Aching
Confusion
Stiff neck
Fever that has persisted for more than 48 hours
Regardless of their body temperature, the following signs and symptoms indicate an infant, child, or nonverbal adult should receive medical attention:
Behavioral changes (such as being less alert, not smiling, not playing, prolonged extreme fussiness or agitation)
Decreased appetite or refusing food
Abnormal skin color
Decreased urine output
Changes in bowel pattern
Breathing difficulties
Passing out
Treating a Fever at Home
Here are a few remedies that may help treat a fever at home:
Drink plenty of fluids, including water, ice pops, soup, and gelatin.
Take over-the-counter (OTC) fever-reducing medications such as Advil or Motrin (ibuprofen) or Tylenol (acetaminophen).
Place a cool towel under the arms, behind the neck, and on the forehead.
Take a lukewarm (not hot, but not overly cold) bath.
Keep the room temperature comfortable, not overly hot or cool.
Remove excess clothing or blankets.
The following are safety considerations when treating a fever at home:
Avoid giving medications to infants 3 months or younger before calling your child's provider.
Do not use ibuprofen in children 6 months or younger.
Do not give aspirin to a child unless your child's provider tells you to. It can cause a serious illness called Reye's syndrome.
Avoid bundling with multiple blankets or jackets, even if you, another adult, or a child has the chills.
Do not use cold baths, ice, or alcohol baths as they can cause shivering and increase core body temperature, which can be dangerous. Lukewarm baths are fine and helpful.
Avoid too much sugar when taking in fluids.
Do not force food on someone who is refusing it.
Associated Factors in Normal Temperature Readings
As mentioned above, age, temperature measurement site, and the time of day factor into your normal body temperature. Sex also plays a role. People assigned female at birth tend to have higher temperatures. This also fluctuates during their menstrual cycle, ovulation, and pregnancy.
Other factors include:
Physical activity
Stress or other strong emotions
When you eat
Heavy clothing or blankets
Hot or humid environments
Health conditions, including hypothyroidism, autoimmune disorders, and some types of cancer
Immunization (children may respond with a low-grade fever)
Teething (elevated temperature, not usually get higher than 100)
Some medications
Summary
The average human body temperature is 98.6 degrees F. Healthy, normal body temperatures range from 96 to 99.9 and vary across the lifespan. Several factors can affect body temperature, including age, sex, and where on your body you take it.
Fevers often occur when your body is fighting an infection and they may occur with other symptoms, such as nausea or a stiff neck. This can suggest a serious underlying health problem that requires medical attention.
A body temperature over 100.4 is considered a low-grade fever; temperatures above 103 are a high-grade fever; and temperatures over 105 become more dangerous, especially if untreated. Infants three months or younger with a rectal temperature over 100.4 should see a healthcare provider.
Frequently Asked Questions
Is 98.8 degrees F a fever?
No, 98.8 falls within the normal body temperature range and is not considered a fever. Temperatures that are 100.4 or more are considered a fever.
What’s a high fever temp from COVID-19?
When COVID-19 causes a fever, it’s typically a low- or medium-grade fever. This means it falls between 100.4 and 103.
How do you bring down a fever?
There are several techniques you can try to bring down a fever. These include lukewarm baths, a cool cloth under the arms or on the forehead, and removing excess blankets or jackets. You can also try OTC fever-reducing medications, such as Advil or Motrin (ibuprofen), or Tylenol (acetaminophen).
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