Medically the evaluation by Debra Sullivan, Ph.D., MSN, R.N., CNE, COI — composed by Corey Whelan ~ above December 15, 2020

Share on PinterestADragan/Getty Images
Having a reliable medical thermometer at home have the right to be exceptionally helpful. The capacity to accurately find out if someone has a fever provides you much-needed information around important next actions for their care.

You are watching: For thermometers to read temperatures correctly

There are many species of contact and also contact-free thermometers to choose from. The ages of your family members members, also as personal preference, can aid you recognize which types to buy.

Like any other maker in her home, it’s crucial to understand how your thermometer works. No every form works the same way or is designed to carry out the very same temperature readings.

Guesswork is the last thing you want to rely on as soon as someone is sick. Here’s an introduction of clinical thermometers, how to usage them, and also what their measurements mean.

The different species of medical thermometers

No issue which kind you choose, read the manufacturer’s instructions carefully. No thermometer will carry out accurate results if it’s used incorrectly.

Never use a thermometer top top a human that is supposed for another purpose, such as a activities or meat thermometer. These won’t provide accurate readings.

If you a parent, you might be wondering why we’re omitting forehead strip thermometers from this roundup. Strip thermometers are inexpensive and also quick come use. However, due to the fact that they measure up skin temperature fairly than body temperature, they’re considerably less accurate and should be avoided.

Digital thermometer


Digital thermometers job-related by using warmth sensors that identify body temperature.

They can be provided to take temperature readings in the mouth, rectum, or armpit.

When assessing digital thermometer readings, keep in mind the armpit (axillary) temperature runs around ½ come 1°F (0.6°C) cooler than oral readings. Rectal thermometers run ½ to 1°F (0.6°C) warmer than dental readings.


Digital thermometers carry out accurate readings in about 1 minute or less.


In order come get specific reading from dental use, the reminder of the an equipment must be placed under the tongue through the mouth completely closed. Because that this reason, rectal readings are thought about to it is in the most accurate for babies and small children. Additionally:

Oral readings won’t be exact if they space taken as well close to eat or drinking, because results may be it was crooked by your food or drink’s temperature. Wait at least 15 minutes. Rectal readings may be uncomfortable to acquire for infants and tiny children.You shouldn’t use the very same thermometer for both rectal and also oral readings. This may require the acquisition of two thermometers, which have to be labeled.Batteries in thermometers need to be replaced periodically. Make sure you have actually the right type of batteries on hand because that your an equipment and the you understand how to change them, for this reason you’re no left scrambling in an emergency.

Oral thermometer


Oral temperature have the right to be bring away by either a digital or mercury thermometer. We’ll walk over the benefits and also drawbacks of mercury thermometers below.

The typical oral temperature reading is 98.6°F (37°C). However, any oral temperature from 97°F (36.1°C) come 99°F (37.2°C) is considered typical. Some world run naturally cool, and also others slightly warmer. The a an excellent idea to know what her temperature commonly is for this reason you can assess even if it is you’re running a fever once you feel sick.


Oral thermometers are many accurate in children over 3 and in adults.


Small children and also people v breathing problems may not be able to keep your mouths close up door long sufficient to acquire an accurate reading.

Digital ear (tympanic) thermometer


Tympanic thermometers measure up the temperature inside the ear canal v infrared ray technology.

Tympanic readings are 0.5°F (0.3°C) come 1°F (0.6°C) higher than dental temperature readings.


Tympanic thermometers provide fast and also accurate readings and also may it is in preferable to dental or rectal thermometers, especially in children.

DrawbacksDue to the dimension of the ear canal, tympanic thermometers aren’t recommended for babies under 6 months old.They need to be positioned correctly in bespeak to obtain accurate results.Obstructions choose earwax might skew results.They might not fit effectively in a small or bent ear canal.

Forehead (temporal) thermometer


Forehead thermometers usage infrared sensors to measure up the temperature the the superficial temporal artery, which is a branch of the carotid artery.

Some are well-known as non-contact infrared thermometers.

Forehead thermometers that require no physical contact have become an extremely popular for usage in venues such together airports, stores, and stadiums.

Forehead temperature readings run approximately 1°F (0.6°C) cooler than oral temperature readings.

BenefitsTemporal thermometers administer quick readings, within number of seconds.They are quickly administered and can be provided on infants, children, and also adults.DrawbacksForehead thermometers need to be positioned accurately and also according come the manufacturer’s instructions, or they will not provide the appropriate reading.Readings deserve to be influenced by outside factors, consisting of drafts, wind, at home heating, and also direct sunlight.Wearing specific clothing, such as hats or hefty coats, have the right to skew the results.

App-based thermometer

Most complimentary phone apps designed to take it temperature readings are meant because that recording the temperature of environments, no people.

Phone apps that help with acquisition people’s temperatures depend on digital thermometers the link back to the application via Bluetooth connection.

BenefitsTemperatures deserve to be taken orally, rectally, or under the arm.They carry out readings in ~ 8 come 10 seconds.Some apps let you upload your anonymous temperature readings come a health and also weather map, i m sorry can help make regional authorities mindful of illness spikes in your geographic area.Some apps carry out suggestions for clinical next steps, based on the reading.Most apps administer you through the ability to store a log of many people’s temperatures.DrawbacksApp-based thermometers may be significantly more expensive than digital thermometers without Bluetooth connectivity.

Pacifier thermometer

If your baby uses a pacifier, this may be one easy method for girlfriend to document their approximate temperature.


Ease of usage is the biggest benefit of pacifier thermometers.


Pacifier thermometers need to remain in the mouth, without moving, for approximately 6 minutes. Additionally, they provide an approximation of temperature quite than precise reading.

Mercury (liquid in glass) thermometer

Mercury thermometers were as soon as the just option available for taking temperature.

Due to safety concerns, castle no longer widely available and may also be illegal where you live.

BenefitsMercury thermometers administer accurate temperature readings and also can be supplied orally, rectally, or under the arm.They don’t call for batteries.DrawbacksSince they’re make from glass, mercury thermometers might break easily, permitting toxic mercury come escape.They may additionally cause cuts or glass splinters if they break.Since they contain a hazardous substance, mercury thermometers need to be disposed the properly and can’t be thrown into the trash.They deserve to be hard to read and also must remain in location for 3 minutes.
What kind of thermometer is the many accurate?

The finest thermometer is the one that you deserve to use many comfortably and correctly. It’s additionally helpful if her thermometer comes from a reliable manufacturer.

Rectal thermometers room still considered by plenty of medical experts to be the gold traditional for babies and also children. However, oral and also forehead readings are additionally typically an extremely reliable in these age groups.

Always save in mind that temperature readings vary, based upon how the thermometer is administered:

Rectal thermometer readings will be around 0.5°F (0.3°C) come 1°F (0.6°C) higher than oral temperature readings.Tympanic thermometer readings are generally 0.5°F (0.3°C) to 1°F (0.6°C) higher than oral temperature readings.Axillary thermometer readings deserve to be 0.5°F (0.3°C) come 1°F (0.6°C) reduced than oral temperature readings (and might be the the very least reliable).Temporal thermometer readings are regularly 0.5°F (0.3°C) to 1°F (0.6°C) reduced than oral temperature readings.

To take temperature orally through a digital thermometer:

Wash her hands.Make certain your thermometer is clean and has working batteries.Turn the thermometer on. Slip the plastic sheath over the bottom pointer of the thermometer.The thermometer will show that it’s ready to be supplied with a sound, light, or both.Place the thermometer’s reminder underneath the tongue. Some thermometers come with grooves that show how much into the mouth it need to go.Keep your mouth closed till you listen a beep or similar form of sound.Remove the thermometer and also read it.Rewash your hands.Clean the thermometer in between uses according to the manufacturer’s directions, even if only one person is making use of it.

To take someone’s temperature rectally through a digital thermometer:

Wash your hands.Make certain your thermometer is clean and also has functioning batteries.Cover the guideline of the thermometer v a plastic sheath and apply lubricant, such together petroleum jelly or a water-based lubricant such together K-Y jelly.Babies have the right to be put on your backs, through their legs in the air. Children and adults may be much more comfortable lied on your stomachs.Turn the thermometer on and wait for it to tell friend it’s ready.Keeping the thermometer straight, tenderness insert the tip of the thermometer right into the rectum, no more than 1 inch.Hold it in place so it no slip out.Wait come hear a beep or comparable sound.Remove the thermometer and read it.Clean the thermometer according to the manufacturer’s directions prior to storing or reusing.Rewash your hands.

If your boy is squirming, it may be difficult to get an accurate reading. If so, eliminate the thermometer and use a different thermometer to take it an oral, armpit, or forehead reading.

No-touch forehead thermometers usually have a removable cap the keeps that clean during storage. Make certain you take it the cap off prior to use.

Activate the an equipment with the strength button. You’ll know it’s ~ above if it lights up and also a startup succession loads.When her thermometer is ready, place it no much more than 2 inches away from the facility of the forehead. You can likewise touch the forehead through some models. Either way, you’ll gain the many accurate reading feasible if the forehead is clean and clear of hair.Many thermometers have actually a accuse light the takes the guesswork the end of positioning. Make certain to hold the thermometer steady. The thermometer and forehead have to be free of movement in order come get an exact reading. Press the temperature button.Your an equipment will beep or flash to permit you know the temperature is all set to be read. This will only take roughly 2 seconds.

See more: What Is 200 Grams Equal How Many Ounces Converter, Convert 200 G To Oz

Instructions for forehead thermometers vary by manufacturer, so make certain to read and also hold onto the instructions or user’s hand-operated that come v your device.