Getting an accurate measurement of your child's temperature takes practice. If you have questions about these instructions, ask your healthcare provider to show you how it's done. Then ask your provider to watch you do it.
A rectal (in the bottom) temperature or a temporal artery temperature are the most accurate. Temperatures measured by mouth, by electronic pacifier, or by ear are also accurate if done properly. Temperatures measured in the armpit are the least accurate, but they are better than no measurement. The best place to use the thermometer depends on the age of your child.
An armpit temperature is best because it is safest and works fine for a quick check. If the armpit temperature is over 99°F (or 37.2°C), double check it with a rectal temperature. It is good to double check with a rectal temperature because if your baby has a true fever, you should see a healthcare provider immediately.
A rectal temperature or electronic pacifier thermometer are best. Using a temporal artery or ear thermometer is fine after 6 months old. An armpit temperature is fine for a quick check if done correctly.
Take the temperature by mouth (orally), or use a temporal artery or ear thermometer.
The American Academy of Pediatrics urges parents not to use glass mercury thermometers due to safety issues with mercury and broken glass. They measure temperatures slowly and are often hard to read. If you still have one of these thermometers, ask your healthcare provider how to dispose of it.
Digital electronic thermometers measure temperatures with a heat sensor and require a button battery. They measure temperatures quickly, usually in less than 30 seconds. The temperature is displayed in numbers on a small screen. The same thermometer can be used to take rectal, armpit, and oral temperatures.
Digital thermometers come in many sizes and shapes. You can get them at most supermarkets and pharmacies, and they are available in a range of prices.
Many hospitals and medical offices now take your child's temperature using an infrared thermometer that reads the temperature of the eardrum. In general, the eardrum temperature provides a measurement that is as accurate as the rectal temperature.
The biggest advantage of this thermometer is that it measures temperatures in less than 2 seconds. It also does not require cooperation by the child and does not cause any discomfort. Ear thermometers for use at home have been developed and they cost $30 to $40. The American Academy of Pediatrics (AAP) advises against using electronic ear thermometers for infants younger than 3 months because their ear canals are usually too small.
These infrared thermometers read the temperature of the blood within the temporal artery. A temporal artery crosses the forehead on each side of the head. The readings are more accurate than ear temperatures. Their main advantage is that the temperature can be taken in seconds and without awakening the child. The disadvantage is that they cost more than any other thermometer, about $60.
The new electronic pacifier thermometers have a heat sensor and are powered by a button battery. These pacifiers let you measure oral temperature in younger children. To get an accurate reading, the child needs to keep the pacifier in the mouth for 3 minutes without moving. This is very difficult for most babies and toddlers.
Liquid crystal strips put on the forehead have been studied and have been found to be inaccurate. They do not detect an elevated temperature in most children with fever.
Touching the forehead is somewhat reliable for detecting fevers over 102°F (38.9°C) but tends to miss mild fevers.
Temperatures can be measured in degrees Fahrenheit (F) or degrees Celsius (C). The table below shows the temperatures in degrees Celsius that are equivalent to temperatures measured in degrees Fahrenheit:
95 degrees F = 35 degrees C 96.8 degrees F = 36 degrees C 98.6 degrees F = 37 degrees C 99 degrees F = 37.2 degrees C 99.5 degrees F = 37.5 degrees C 99 degrees F = 37.2 degrees C 100 degrees F = 37.8 degrees C 100.4 degrees F = 38 degrees C 101 degrees F = 38.3 degrees C 102 degrees F = 38.9 degrees C 103 degrees F = 39.5 degrees C 104 degrees F = 40 degrees C 105 degrees F = 40.6 degrees C 106 degrees F = 41.1 degrees C 107 degrees F = 41.7 degrees C 108 degrees F = 42.2 degrees C