Axillary, or underarm, temperature reading, although commonly used, is the least accurate method. For infants, you should use the rectal method, which is the most accurate, as even a slight fever in a newborn can prove to be very dangerous. For anyone over three months of age, an axillary reading is sufficient, if done properly. Although the exact amount of time required varies, all digital thermometers should read temperature in two minutes or less.
Buy a digital thermometer from your local pharmacy. Although price varies, you should be able to find a decent one for around $10.
Clean the thermometer with rubbing alcohol before first use.
Wait at least twenty minutes after eating, exercising or bathing before attempting to take temperature, as these things may affect the result.
Press the button to turn on the digital thermometer. Wait until the display indicates that it is ready.
Insert the bulb of the thermometer under the arm, fully into the armpit, so that it is in contact with skin. Make sure it is not in contact with clothing.
Remain still and wait for the thermometer's beep to signal that it is finished. After the beep, promptly remove the thermometer.
Add one degree to the temperature displayed. For example, if the thermometer reads the temperature as 97.6 degrees Fahrenheit, add one degree, making it 98.6 degrees, which is a normal body temperature.
Although normal body temperature is commonly considered to be 98.6 degrees Fahrenheit, it is also considered normal to be one degree above or below that.