The thermometer you can trust is the right type for the person you are checking, used the way its instructions say. For a baby under 3 months, the American Academy of Pediatrics (AAP) says a rectal reading with a digital thermometer is the most accurate. For children under 5, the NHS says to use a digital thermometer under the armpit. For older children and adults, a good forehead, ear or mouth thermometer is fine if you use it properly.
Then there is the thermometer itself. Every one below has an FDA 510(k) clearance that covers its exact model, and published clinical accuracy: either a clinical study reported in the FDA summary, or peer reviewed studies its maker publishes. Every card links to that evidence so you can read it yourself. Then, and only then, it also had to be well rated by buyers on Amazon.
The short version
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Best overall
iHealth No-Touch Forehead Thermometer (PT3)iHealth No-Touch Forehead Thermometer (PT3)No touch, a reading in a second, and a clinical study covering babies to adults. Full review
$19.99 on Amazon Amazon Price as of Oct 31, 11:09 AM UTC Amazon UK -
Best forehead scan for any age
Exergen TemporalScanner TAT-2000CExergen TemporalScanner TAT-2000CTemporal artery scanning, which the AAP says works at all ages. Full review
$38.69 on Amazon Amazon Price as of Oct 31, 11:09 AM UTC Amazon UK
Both picks passed both checks in the US and the UK. Both are forehead thermometers. We have not yet found a digital stick thermometer that passes: none we checked had an Amazon listing whose model number matches an FDA clearance exactly. A stick is what you need for a young baby’s rectal reading, or for the NHS armpit method, so see which type to buy below; we will add one as soon as one qualifies.
Which type of thermometer is most accurate?
The AAP ranks the places you can take a temperature. In its words, rectal temperatures “are the most accurate,” forehead temperatures “are the next most accurate,” oral and ear temperatures “are accurate if done properly,” and armpit temperatures “are the least accurate,” though they can be used to screen a child of any age.
For children, age decides which of those the AAP says you can use:
| Child’s age | Types the AAP says you can use |
|---|---|
| Under 3 months | Rectal (digital stick) gives the best reading; forehead (temporal artery) works at any age |
| 3 to 6 months | Rectal or forehead (temporal artery) |
| 6 months to 4 years | Rectal, forehead or ear |
| 4 years and up | Mouth, forehead or ear |
The NHS keeps it simpler: “always use the thermometer in the armpit with children under 5 years,” with a digital thermometer, which it says gives “a fast, accurate reading.”
The two bodies agree on the essentials: use a digital thermometer, and never use an old glass one with mercury. The AAP says to remove any mercury thermometer from your home, and the NHS warns they “can break, releasing small splinters of glass and highly poisonous mercury.”
They differ on the details. The AAP says ear thermometers can be used from 6 months, because younger babies’ ear canals are too narrow. The NHS says ear thermometers “can give misleading readings if you do not put them in the ear correctly, which is more likely to happen with babies.” Both say forehead strips are not reliable: the NHS says they show “the temperature of the skin, rather than the body,” and the AAP lists them, along with pacifier thermometers, as less accurate screening tools.
If you follow the NHS, you need a digital stick for the armpit; any pharmacy sells them. If you follow the AAP, a rectal stick for a young baby, and a forehead thermometer for everyone else is a reasonable pair. Neither of our picks is a stick, so for a baby under 3 months, or for the NHS method, buy a simple digital stick from a pharmacy as well.
What “FDA cleared” means for a thermometer
Thermometers are medical devices, and most have reached the US market through a 510(k) clearance. Many clearance summaries describe a clinical study run under the standard for clinical thermometers (ISO 80601-2-56, and ASTM E1965 for infrared models), comparing the thermometer with a reference on real people and reporting clinical bias and repeatability. That is the “published clinical accuracy” we look for, either in the FDA summary or in studies the maker publishes. The evidence for each pick is linked from its card.
You can check any thermometer yourself in the FDA 510(k) database: search by product code FLL (clinical electronic thermometers) or by company name, open the entry, and compare the device name or model number with the one on the box.
Two things are worth knowing. First, model numbers matter. Brands sell near-identical thermometers under different numbers, and several we looked at were sold under a model number that no clearance names. We only list an exact match. Second, since June 2025, most new thermometers no longer need a 510(k). The FDA exempted clinical electronic thermometers (except continuous and thermal imaging ones) from premarket review, as long as appropriate testing such as ISO 80601-2-56 validates their performance. New models may now reach shelves with no FDA review to check. We only list models that have a clearance on record.
The picks
iHealth No-Touch Forehead Thermometer (PT3)
A no-touch forehead thermometer that reads from about an inch away and shows the result in a second, with a vibration instead of a beep. The PT3 is named in its FDA 510(k) clearance for people of all ages, and the clearance summary reports a clinical accuracy study in babies, young children and adults.
- Model
- PT3
- Type
- Infrared, no touch, center of the forehead
- Ages
- All ages (FDA clearance)
- Reading
- About 1 second, vibration alert
- Power
- 2 AAA batteries, included
The proof: FDA 510(k) K200531 510(k) summary with clinical study
Best for
A quick check on a sleeping child, or a household that wants one thermometer for everyone.
Worth knowing
Forehead readings are affected by sweat, a cold forehead after being outside, or hair in the way. The AAP lists forehead thermometers as the next most accurate after rectal; for a baby under 3 months, it says a rectal reading is best.
The PT3 reads your temperature from about an inch away, in a second, and buzzes rather than beeps, so it works on a sleeping child. Its FDA clearance covers all ages, and the clearance summary reports a clinical study of 130 people across three groups: babies under 1, children aged 1 to 5, and older children and adults. It is one of the most bought thermometers on Amazon in both countries. Like any forehead thermometer, it needs a dry forehead and a few minutes indoors after coming in from the cold.
Exergen TemporalScanner TAT-2000C
A temporal artery thermometer: you place it on the middle of the forehead and slide it across to the hairline while it scans the artery under the skin. Exergen introduced the method. The FDA device database records the TAT-2000C under Exergen's TemporalScanner 510(k) clearance, and Exergen publishes the peer reviewed clinical studies of its temporal artery thermometers.
- Model
- TAT-2000C
- Type
- Temporal artery scan, forehead to hairline
- Ages
- All ages, including newborns (maker)
- Extras
- Soft glow display, silent mode
- Power
- 9V battery, included
The proof: FDA 510(k) K011291 FDA device record for the TAT2000C Exergen clinical studies
Best for
Parents who want a forehead thermometer that the AAP says can be used at any age, including newborns.
Worth knowing
The technique matters: slide in a straight line to the hairline, and keep the button pressed. On amazon.co.uk it is a US import, so check the delivery details and the display units before you buy.
The TAT-2000C is a temporal artery thermometer, the type the AAP says “can be used for all ages.” Instead of pointing it at the forehead, you slide it across from the middle of the forehead to the hairline. The FDA device database records the TAT-2000C under Exergen’s TemporalScanner clearance, and Exergen publishes peer reviewed studies of its temporal artery thermometers. Exergen has since released an updated TAT-2000C+; we link the TAT-2000C because that is the model we matched to the FDA record.
Getting an accurate reading
A good thermometer still gives a misleading number if it is used wrongly. From the AAP, the NHS and the FDA:
- Follow the instructions for your model. The AAP and the FDA both say this first, because each thermometer has its own distance, position and timing.
- Let the child settle first. The NHS says a reading can be slightly off if your child has been wrapped in a blanket, very active, in the bath or wearing a lot of clothes. Let them cool down for a few minutes, without letting them get cold or shivery, and take it again.
- Wait after coming in from the cold. The AAP says cold weather can make an ear reading low and suggests waiting 15 minutes indoors. The FDA says forehead thermometers should be used out of direct sun and drafts, on a forehead that is clean, dry and not covered.
- Wait 30 minutes after a hot or cold drink before taking a temperature by mouth (AAP).
- Rectal readings: a little petroleum jelly on the tip, and only half an inch in for babies under 6 months (AAP).
Both the AAP and the NHS treat 38°C (100.4°F) or higher as a fever. The AAP says to call your pediatrician right away if a baby 2 months or younger has a rectal temperature of 100.4°F or higher. The NHS says to ask for an urgent GP appointment or call 111 if a baby under 3 months has a temperature of 38°C or higher, or a baby aged 3 to 6 months has 39°C or higher. Fever is one sign among several, and both bodies list other symptoms that need help sooner.
What did not make the list
Several well-known thermometers are missing on purpose:
- Braun ThermoScan 7 (IRT6520). It is one of the most popular ear thermometers in both countries, but we could not find an FDA clearance that names it, and the FDA device database lists it without a 510(k) number. We will add it if we can match it to a clearance.
- Braun ThermoScan 3 (IRT3030) and Kinsa QuickCare. Both are FDA cleared, but their clearance summaries say no clinical testing was done on them; they were cleared on lab testing and their similarity to older models.
- Braun No Touch + Forehead (NTF3000) on amazon.com. The NTF3000 is cleared, but the Amazon listing names model BNT300US, which no clearance names.
- Vicks ComfortFlex (V966). A popular digital stick, made by Microlife, whose model MT18L1 is FDA cleared with clinical studies. Kaz, which sells Vicks thermometers, names the V966 as that model in its own FDA filing, but the clearance itself names only the MT18L1 and the Amazon listing gives no model number, so it is not an exact match.
- Braun Sensian 7 No Touch + Forehead (BNT400). The BNT400 is FDA cleared, with a clinical study. The amazon.co.uk listing is the BNT400BWE, a different model number from the one cleared, and on amazon.com buyers rated it below our bar.
- Vicks RapidRead (VDT972). It is cleared, with a published clinical study, but buyers rated it below our bar.
- Most unbranded forehead and ear thermometers. Many say “FDA approved” or “medical grade” without a clearance we could match to the model on the listing.
A trustworthy reading comes from the right type for the age, a cleared model, and the instructions followed every time. If a reading worries you, call your doctor, your pediatrician or NHS 111 rather than relying on the number alone.