Teething might nudge the thermometer. It does not push it past 38C. If you are reading a real fever, stop blaming the tooth and start thinking about illness.
What the reading means
| Thermometer reading | What it is | What to do |
|---|---|---|
| Below 38C (100.4F) | A slight rise, which can happen while a tooth comes through | Comfort as usual. Nothing here needs treating as a fever |
| 38C (100.4F) or above | A fever. Teething does not explain it | Contact your pediatrician or doctor |
| Any reading with vomiting, diarrhea or a spreading rash | Not a teething picture | Contact your pediatrician or doctor |
The short version.
- Teething can raise a temperature a little, and that is all it can do
- 38C or 100.4F is the line most guidance draws, and it is the safer one to use
- A fever is a reason to look for an infection, not a reason to check the gums
- The number matters more than how your baby is behaving, because babies with real infections can seem fine for hours
- There is no such thing as a teething fever that runs for days
- If you are unsure, the call costs you nothing
Why your searches give you two different numbers
Here is the thing nobody mentions. The published guidance does not agree with itself about where the line sits, and if you have read two pages and come away confused, that is why.
| Source | Where it puts the ceiling |
|---|---|
| NHS | temperature "slightly raised but less than 38C" |
| Cleveland Clinic | a fever above 100.4F (38C) is "not due to teething" |
| American Academy of Pediatrics, teething guide | a slight rise, "but not over 101 degrees Fahrenheit or 38.3 degrees Celsius" |
| American Academy of Pediatrics, pain guide | fever is "a false symptom of teething" |
Two things are going on. The first is that the AAP says different things in two different places, one allowing a rise up to 38.3C and the other calling fever a false symptom outright. That is not a trick of reading, it is two pages written at different times.
The second is that the gap between 38C and 38.3C is small on paper and meaningless at 2am with a hot baby.
Use 38C, or 100.4F. It is the lower of the two, three of the four sources point at it, and treating a 38.1C reading as worth a phone call costs you a phone call. Treating it as teething can cost a great deal more.
What the research found, precisely
This part is worth quoting exactly, because it is almost always paraphrased into something it does not say.
A 2016 meta-analysis pooled 16 studies covering 3,506 children up to three years old and concluded that a tooth erupting "could lead to a rise in temperature, but it was not characterized as fever."
Read that again. Not no change. Not a fever. A rise that did not reach the threshold. That is a narrower and more useful finding than either of the things people usually claim, and it matches what the guidance says.
A larger review published in 2025 pooled 25 studies and put the overall prevalence of teething problems at 80%, with increased biting and irritability as the most common complaints. Teething is genuinely uncomfortable for most babies. The discomfort is real. The fever is not part of it.
How high can a teething temperature get?
Not past the line above. Anything you would describe as high is not teething.
If your thermometer is reading 101F, 102F or 103F, you are outside everything the guidance allows for teething, by both the strict threshold and the generous one. A reading in that range during teething is a reading that happens to coincide with teething. Those are different things, and the second one is a coincidence of timing that gets babies sent home undiagnosed.
Teeth arrive on and off across roughly the first two and a half years. Your baby will be teething during most of the illnesses they catch in that period, simply because the windows overlap. Overlap is not cause.
How long does it last?
The honest answer is that this is the wrong question, and asking it is usually a sign something is being missed.
A slight rise connected to a tooth coming through tracks the tooth, so it is a matter of hours rather than days. Nothing in the guidance describes a teething temperature that persists. So a raised temperature running into a second or third day is not behaving like teething, and the length of it is itself the reason to stop waiting and make the call.
Teething or illness? How to tell
You often cannot, and that is the useful thing to know rather than a failure on your part. The signs overlap: a baby who is miserable, off their food and not sleeping looks much the same whether a molar is coming or a virus is starting.
What separates them is not how your baby seems. It is the number, and what else is happening.
Pointing toward teething: a slight rise, drooling, chewing on everything, a sore red gum you can see, a rash in the dribble zone, and a baby who settles with comfort.
Pointing away from it: 38C or above, vomiting, diarrhea, a rash anywhere dribble does not reach, a cough, unusual sleepiness, or a baby you cannot settle at all.
The second list is not a list of worse teething. It is a list of reasons to get someone to look at your child.
Do molars make it worse?
Molars are bigger and blunter than the front teeth, and parents report a harder time with them. What does not change is the ceiling: a molar coming through has the same effect on temperature as an incisor, which is to say very little. Our baby teeth chart shows which teeth are due at your baby's age if you want to know what you are dealing with.
A high temperature during molars is a high temperature during molars. The tooth does not earn extra latitude for being large.
What to do about a slight rise
Very little, which is the point.
A temperature under the threshold in a baby who is otherwise themselves needs comfort, not treatment. Keep fluids up, keep the room comfortable, and deal with the thing actually bothering them, which is the gum. For that, the approved options are a clean finger, a cool spoon, a damp flannel or gauze pad, and a teether made of solid rubber.
Never use teething gels to numb the gums. The AAP warns that in rare cases they can poison a baby's blood cells and stop them carrying oxygen.
Do not reach for fever medicine to treat teething. If the reading is low enough to be teething, there is no fever to bring down. If it is high enough to need medicine, the reason to call is already there, and medicine taken first can mask what the doctor needs to see.
When to call your pediatrician
Get in touch with your pediatrician or doctor if your baby has:
- A temperature of 38C or 100.4F or above
- A raised temperature alongside diarrhea or vomiting
- A raised temperature that is still there after a day or so
- A rash that is spreading, or sitting anywhere dribble cannot reach
- Unusual sleepiness, or a baby you cannot settle
- Anything that worries you, including something you cannot put a name to
This guide is general information, not medical advice. For your child's health or development, speak to your pediatrician or doctor.
Frequently asked questions
Does teething cause a fever?
No. Teething can raise a baby's temperature slightly, but not to 38C or 100.4F. A reading at or above that is a fever, and teething does not account for it. A 2016 meta-analysis found that an erupting tooth could raise temperature without reaching the level of a fever.
What temperature is too high for teething?
38C, or 100.4F. The AAP's teething guide allows slightly more, up to 38.3C or 101F, but the lower figure appears in most guidance and is the safer one to work from. Above the line, treat it as illness and get advice.
How long can a teething fever last?
There is no such thing to measure. A slight rise connected to a tooth tracks the tooth and is a matter of hours. A raised temperature carrying on for a day or more is not behaving like teething and is worth a call.
Can teething cause a fever of 101 or 102?
No. Both readings are above every threshold in the published guidance, including the most generous one. A temperature in that range during teething is a temperature that happens to arrive while your baby is teething.
Is it teething or is my baby sick?
Often you cannot tell from how they seem, because the two look alike. What tells you is the thermometer and the company the temperature keeps. A slight rise with drooling and gum-chewing fits teething. A fever, vomiting, diarrhea or a rash outside the dribble zone does not.
Do molars cause a fever?
No more than any other tooth. Molars are blunter and parents often find them harder going, but the effect on temperature is the same, which is a slight rise at most.
My baby feels hot but the thermometer is under 38C. What now?
Treat your baby, not the number, and keep checking. A reading under the threshold in a baby who is otherwise themselves does not need fever treatment. If they seem unwell to you, that is reason enough to call, whatever the thermometer says.
Sources
- Teething Pain Relief, American Academy of Pediatrics. Fever described as a false symptom of teething, and the warning on teething gels.
- When Does Teething Start? American Academy of Pediatrics. The slight rise "but not over 101 degrees Fahrenheit or 38.3 degrees Celsius", and the instruction to consult a pediatrician above it.
- Teething (Teething Syndrome), Cleveland Clinic. The 100.4F and 38C line, the contact-your-provider list, and the solid-rubber teether guidance.
- Baby teething symptoms, NHS. The "slightly raised but less than 38C" wording.
- Massignan C, Cardoso M, Porporatti AL, et al. Signs and Symptoms of Primary Tooth Eruption: A Meta-analysis. Pediatrics. 2016;137(3):e20153501. The temperature conclusion quoted above. doi:10.1542/peds.2015-3501.
- Garima J, Mathur VP, Tewari N, et al. Global prevalence of teething problems in infants and children, a systematic review and meta-analysis. International Journal of Paediatric Dentistry. 2025 May. Twenty-five studies, 80% overall prevalence, increased biting and irritability most common. doi:10.1111/ipd.13272.
Both reviews pool observational studies rather than trials, and the 2016 authors noted that symptom definitions varied between the studies included. Read the prevalence figures as an indication of how common discomfort is, not as precise rates.
More from our teething cluster
- When Do Infants Start Teething?. The 4 to 7 month window, and why three health bodies give three different answers.
- Teething Rash. Where a dribble rash appears, and why a rash on the body is not teething.