Table of contents:
- Normal body temperature
- What temperature is fever
- How to measure temperature correctly
- What to do to lower a fever

2023 Author: Benjamin Dyson | [email protected]. Last modified: 2023-05-27 20:34
Usually, it is considered a fever when the axillary temperature is above 38ºC, since temperatures between 37, 5º and 38ºC can be easily reached, especially when it is very hot or when you have many layers of clothes on.
The surest way to know if you have a fever is to use a thermometer to measure your body temperature, not just putting your hand on your forehead or the back of your head.
Often, the high temperature can be reduced naturally, by removing an item of clothing or taking a bath with warm, almost cold water, for example. However, in cases where the temperature in the armpit is higher than 39.6ºC, it is recommended to seek medical attention, as the use of medication may be necessary. See the main ways to lower the fever.

Normal body temperature
Body temperature is considered normal when it varies between 35.4ºC and 37.4ºC, as long as it is measured in the armpit.
How to know if you have a fever
To know if your temperature is normal or if it is a fever, please enter the value in our calculator:
What temperature is fever
It is considered fever when the axillary temperature is above 38ºC, however, depending on the value, the temperature can be classified in different ways:
- Slightly increased (subfebrile): between 37.5ºC and 38ºC. In these cases, other symptoms usually appear, such as chills, tiredness, tremors or redness of the face;
- Fever: above 38ºC.
- High fever: above 39.6ºC. It should be considered a medical emergency and therefore you should go to the hospital.
In babies and children, temperature measurement in the anal region is also relatively frequent. In these cases, most pediatricians consider fever from 37.8º C.
37, is 5ºC a fever?
A temperature of 37.5ºC is not considered a fever, indicating that the body temperature is slightly increased, which could be due to wearing very warm clothes or being in the sun for a long time, for example.
However, this temperature can also be indicative of the beginning of an infectious or inflammatory process and, therefore, it is interesting that the temperature is monitored throughout the day to see if it increases, especially if other symptoms appear.
How to measure temperature correctly
To measure body temperature correctly it is first important to know how to use each type of thermometer. The most common are:
- Digital thermometer: place the metal tip in the armpit, anus or mouth in direct contact with the skin or mucous membranes and wait until the sound signal to check the temperature;
- Glass thermometer: place the thermometer tip in the armpit, mouth or anus, in direct contact with the skin or mucous membranes, wait 3 to 5 minutes and then check the temperature;
- Infrared thermometer: Point the thermometer tip towards the forehead or into the ear canal and press the button. After the "beep" the thermometer will show the temperature immediately.
Body temperature should be measured at rest and never immediately after physical activity or after a shower, because in these cases it is normal for the temperature to be higher and, therefore, the value may not be real.
How to take a baby's temperature
Body temperature in babies should be measured with a thermometer, as in adults, and preference should be given to more comfortable and faster thermometers, such as digital or infrared.
The ideal place to assess the baby's temperature more accurately is the anus and, in these cases, a digital thermometer with a soft tip should be used so as not to hurt the baby. However, if parents do not feel comfortable, they can use the armpit temperature measurement, confirming the anal temperature only at the pediatrician, for example.
What to do to lower a fever
There are some natural ways to lower your body temperature and relieve a fever, such as removing excess clothing, taking a warm bath, or applying cold compresses to your forehead and face. See other natural ways to reduce fever.
However, depending on the cause, there are cases where it is necessary to use medication. The drug most used to lower fever is paracetamol, which can be taken up to 3 times a day, at intervals of 6 to 8 hours. The dosage of paracetamol should always be indicated by a doctor, especially in the case of children, as it varies according to body weight. Learn more about fever-reducing remedies.