Parents often get confused about what is the best way to take their child's temperature and what kind of thermometer they should buy.
In general, except for very young infants, it actually isn't that important. For these children under about three months old, a rectal thermometer is the most accurate way to check your child's temperature.
Shop online: Safety 1st 10 Second Digital Thermometer that can be used to take a child's temperature rectally, orally, or under their arm.
Even if you use a different method to take your younger infant's temperature, you should confirm it with a rectal thermometer to be safe. Even a small difference, like a half a degree, could mean the difference between simple observation and a full sepsis workup with a spinal tap when your 2 or 3 month old has a fever.
For most other children, instead of worrying about which thermometer to use and whether you should add or subtract a degree, you should usually just tell your Pediatrician what the temperature is and how you took it. You can then leave it to him or her to interpret what the temperature means.
Although parents may not believe it, the exact temperature is not usually what your Pediatrician uses to determine how to treat your child. Kids may be acting fine with a fever of 105 degrees or deathly ill with a temperature of just 99. The degree of fever doesn't usually tell you how sick a child is.
The only other clear recommendation is that you should no longer use mercury thermometers. The AAP recommend disposing of them because of the risk of mercury poisoning if they break. If you are still using a mercury thermometer, now would be a good time to choose a replacement to check your child's temperature when you think that they might have a fever.
In addition to be able to take your child's temperature rectally with a digital thermometer, most can also be used under their arm or in their mouth. In general, you can take a temperature rectally in an infant or toddler and under their arm if they are over 3 months old. Once your child is 4 or 5 years old, you can use an oral digital thermometer. Keep in mind that an oral temperature is usually about 1/2 degree less than a rectal temperature.
Remember that taking your child's temperature under their arm (axillary thermometer) is probably the least accurate method and should usually be confirmed by another method if you detect a fever this way, especially in younger children.
Shop online: Digital Thermometer
Tympanic or ear thermometers are very popular because they give a quick reading and are easy to use. You do have to correctly place the ear thermometer into your child's ear canal to get an accurate reading though, which can sometimes be tricky, and they likely won't work if your child has a lot of earwax. And many people do not think that they are very accurate for children less than 12 months old. They are a good choice for most other children though.
Shop online: Ear Thermometers
If your infant or toddler uses a pacifier, a pacifier thermometer can be a good way to take your child's temperature.
Shop online: Pacifier Thermometer
Temporal Artery Thermometers
The new temporal artery thermometers are probably the easiest to use. You simply scan it across your child's forehead, and so can even use it even when your child is sleeping. And you don't need to buy replacement probe covers like you do for most other thermometers.
Shop online: Temporal Artery Thermometer
Whichever thermometer you use, you should make sure that you trust the readings and feel comfortable using it. You might even take your child's temperature 2 or 3 times to see if you are getting consistent readings. Or consider taking your thermometer to your Pediatrician's office at your next visit and compare the reading you get to the one that they record in the office.