What counts as a high temperature
A normal body temperature varies slightly from person to person, but the NHS uses one clear threshold for children: a high temperature is 38°C or more. You might also hear it called a fever.
Your baby may feel hotter than usual to the touch on their back or chest, or feel sweaty or clammy. Touch alone is not reliable, though. If you think your baby has a high temperature, measure it.
How to check your baby’s temperature
The NHS advises using a digital thermometer. For babies and children under 5, place it under the armpit.
- Hold your baby comfortably and place the tip of the thermometer in their armpit.
- Gently hold their arm against their body so the thermometer stays in place.
- Wait for the thermometer to signal that the reading is ready, following the maker’s instructions.
- Note the reading and the time.
Writing down the reading and the time is surprisingly useful. When you call for advice, a health professional will usually ask what the temperature was, when you measured it and how long it has lasted. A temperature that has lasted 5 days or more is itself a reason to get urgent advice.
Why age matters so much
The same reading means different things at different ages. The NHS gives specific thresholds for young babies:
- Under 3 months: a temperature of 38°C or more — or if you think they have a high temperature — needs urgent advice.
- 3 to 6 months: a temperature of 39°C or more needs urgent advice.
For a young baby, do not wait to see whether the temperature comes down on its own. Contact a GP or NHS 111 in the UK, or your local medical service elsewhere, the same day — and use the emergency signs below to decide whether you need an ambulance.
Looking after your baby at home
If your baby has a high temperature but none of the urgent or emergency signs, the NHS describes how to look after them at home:
- Offer plenty of fluids. Keep breastfeeding or giving formula as usual.
- Look out for signs of dehydration, such as fewer wet nappies or a dry mouth.
- Check on your baby regularly, including during the night.
- Do not undress your baby or sponge them with cold water.
- Do not cover them in too many clothes or bedding either.
- Ask a pharmacist, GP or health visitor before giving your baby any medicine.
The advice about clothing can feel counterintuitive. A baby with a fever should be dressed normally for the room — neither stripped down and sponged with cold water, nor bundled up to “sweat it out”.
Medicine
Medicines to bring down a temperature are not suitable for every baby, and the right choice and dose depend on your baby’s age and weight. The NHS advice is simple: ask a pharmacist, GP or health visitor before giving your baby any medicine. Always follow the instructions on the packet and the advice you are given.
This page does not give medicine doses, and Zaripo does not calculate them.
Teething and fever
Parents often wonder whether teething causes a fever. The NHS says teething can cause a slightly raised temperature, but it should be below 38°C. A temperature of 38°C or more, diarrhoea or other signs of illness should not be put down to teething — contact a GP or NHS 111. Our answer on teething explains the usual signs.
Keeping notes while your baby is unwell
When a baby is ill, the details blur. Two adults may each give a feed, take a temperature or change a nappy, and neither has the full picture. A few notes — temperature and time, feeds, wet nappies, anything unusual — help you notice changes and give a clear account if you call for advice.
Zaripo is being prepared as a shared care diary where your family can record feeds, nappies, sleep and notes, and see the latest synced entries. It does not read temperatures, diagnose illness, calculate medicine doses or decide whether your baby needs a doctor. If you are worried, contact a health professional; in an emergency, call your local emergency number.
When to get help
Get urgent advice — contact a GP, health visitor or midwife, or NHS 111 in the UK — if:
- Your baby is under 3 months old and has a temperature of 38°C or more, or you think they have a high temperature.
- Your baby is 3 to 6 months old and has a temperature of 39°C or more.
- Your baby has signs of dehydration, such as fewer wet nappies, sunken eyes or no tears when crying.
- Your baby is not feeding, or is not their usual self and you are worried.
- The high temperature has lasted 5 days or more.
Call your emergency number now — 999 in the UK, 112 in Turkey and most of Europe — if:
- Skin, lips or tongue look pale, blue, grey or blotchy.
- A rash that does not fade when you press a glass against it.
- Your baby is floppy, very difficult to wake or does not stay awake.
- A weak, high-pitched cry that is not like their normal cry, or crying that does not stop.
- Breathing problems: grunting, fast breathing, pauses in breathing, or the skin sucking in under the ribs.
- A stiff neck, or a fit (seizure).
Outside the UK, use your local doctor, health line or emergency number. Trust your instincts: if you are worried about your baby, get help.
Questions parents also ask
What temperature is a fever in a baby?
The NHS defines a high temperature as 38°C or more, measured with a digital thermometer. For babies and children under 5, place it under the armpit.
Is 38°C dangerous for a newborn?
A baby under 3 months old with a temperature of 38°C or more, or who you think has a high temperature, needs urgent medical advice. Contact a GP or NHS 111, or your local medical service, the same day, and call your emergency number if you see any emergency signs.
Should I take my baby’s clothes off if they have a fever?
No. The NHS advises not undressing your baby or sponging them with cold water, and also not covering them in too many clothes or bedding. Dress them normally for the room.
Can I give my baby medicine for a temperature?
Ask a pharmacist, GP or health visitor before giving your baby any medicine. Suitability and dose depend on your baby’s age and weight.
Does teething cause a high temperature?
Teething may cause a slightly raised temperature, but it should be below 38°C. A temperature of 38°C or more is not caused by teething alone, so get advice.