How to take your baby’s temperature and reduce their fever

Your baby feels a little hot, maybe they’re fussier than usual, and suddenly your mind jumps to one thing: do they have a fever? Taking your baby’s temperature sounds simple enough, especially if you’ve got a baby thermometer to hand, but getting an accurate reading (and knowing what to do next) takes a little know-how.

Fever in babies can feel daunting, especially if it’s your first time navigating those warm foreheads and restless nights. But don’t worry, you’re not alone. Whether your little one seems off-colour, extra clingy, or just not quite themselves, we’ve put together a calm, clear guide to help you check their temperature with confidence, understand what those numbers really mean, and know exactly when it’s time to call the doctor.

What is a fever in babies?

A fever is your baby’s way of showing that their little immune system is hard at work. It simply means their body temperature is higher than normal, usually anything over 38°C (100.4°F), and it’s often a sign they’re fighting off a cold, virus, or other infection.

According to Dr. Deborah Lee "the normal temperature for a baby is 36.4C. However, this can vary. A high temperature for a baby is 38C or above."

If you are concerned your baby may be unwell, taking their temperature is a good first step. Babies are not as good at controlling their body temperature as adults. A high temperature is an indicator of infection. "If a baby has a high temperature, it’s important to do all you can to lower it. Babies with a high temperature are at risk of febrile convulsion," says Dr. Lee.

Usually, you will find that in a baby with a fever, their high temperature will settle by itself over a period of a few days. The fever is a normal body response. It is a sign that your baby is fighting an infection which is a common occurrence in baby and childhood.

How to take a baby’s temperature

Use a digital thermometer: You can buy these inexpensively in the pharmacy. "These days, no one uses the old-fashioned glass thermometers filled with mercury, which are liable to break. The head strips you can buy to place on a baby’s forehead, only measure the skin temperature and so are not so accurate. An ear thermometer is not accurate for a small baby as they have very narrow ear canals," says Dr. Lee.

Place the baby on his or her back on a firm surface: It’s easier to do if they are only wearing a nappy. Put the digital thermometer bulb under your baby’s armpit. Hold their arm close to their body to keep the digital thermometer firm in the armpit. Keep the device there for 15 seconds, or however long the manufacturers advice advises.

Be aware that certain things can raise a baby’s temperature, such as being in a warm room, after a warm bath, having been wrapped in warm blankets or being cuddled for a long period. If this is the case, undress the baby and wait a few minutes before taking the reading.

How to reduce a baby’s fever

Medication

Paracetamol: A baby can be given paracetamol to lower their temperature. Paracetamol has antipyretic activity. It inhibits the production of prostaglandins in the brain and switches on some of the body’s hypothermic (cooling) mechanisms.

Paracetamol solution can be purchased under different brand names including Calpol, Disprol, Hedex, Medinol and Panadol. Always check that the preparation is suitable for the age of your baby, says Dr. Lee.

For example, from the age of 2 months, a baby can be given Calpol Infant Suspension 2.5 ml every 4-6 hours but not more than 4 times in 24 hours. For babies under 2 months of age, take specific advice from your GP. Paracetamol can also be given as a suppository to baby from 2 months.

"Also, for any baby, if after two doses of paracetamol, their temperature is not settling, you need to seek urgent medical advice," says Dr. Lee.

Paracetamol is safe and effective when used in accordance with the manufacturer's instructions. This means taking great care to ensure your baby has the correct dose of paracetamol at the correct time intervals. An overdose of paracetamol is all too easy and can be fatal. Always look at the label and read the product information and dosage instructions.

"Use a syringe to correctly draw up the right amount of Calpol. Sit your baby upright and gently squirt the syringe into the back of their mouth, a little bit at a time," says Dr. Lee. You can see a video of how to give medicine to a baby here.

Ibuprofen: Ibuprofen solution can also be given to a baby so long as they are at least 3 months old and weigh 5kg or more. Ibuprofen is a nonsteroidal anti-inflammatory (NSAID). TT also works by inhibiting the production of prostaglandins. Ibuprofen and paracetamol can be given together to help lower a fever in babies aged 3 months and above. "However, an ibuprofen solution has to be prescribed by a doctor," adds Dr. Lee.

"Babies and children should never be given aspirin under the age of 16 years," says Dr. Lee.

Fluids: Keep your baby as well-hydrated as you can. Continue to breastfeed or bottle feed them as normal. They may want little sips more often rather than one big feed. For a baby under 6 months of age, you can give them some boiled, cooled, tap water in a bottle. Babies over 6 months can drink ordinary tap water from a beaker or cup.

Keep them cool: Keep them in a cool environment. A room temperature of 18°C is recommended. Do not overdress them. But note that undressing and tepid sponging is not recommended. "The temperature is a sign of their normal body defence mechanisms so to some extent it’s a necessary part of their recovery. You can use a fan in the room but do not aim it directly at your baby," says Dr. Lee.

Watch them carefully

Keep a careful eye on them to monitor their progress. If their temperature doesn’t come down and stay down after two doses of paracetamol, you need to contact your GP urgently or ring 111.

Look out for signs of dehydration such as

"If any of these are present, contact your GP urgently or ring 111," says Dr. Lee.

When to call for help

The NHS advises you to contact your GP or phone 111 in the following situations

"If your baby has a fever and a rash that does not disappear when you roll a glass jar over it, phone 999 or go to A&E immediately," adds Dr. Lee.

Meet the expert

Having worked for many years in the NHS, mostly as Lead Clinician within an integrated Community Sexual Health Service, Dr Deborah Lee now works as a health and medical writer, with an emphasis on women's health, including medical content for Dr Fox pharmacy. She has published several books and remains passionate about all aspects of medicine and sexual health. After completing her Medical Degree at University of Southampton Medical School in 1986, Dr Lee trained as a GP and after a number of years specialised in Sexual & Reproductive Health (S&RH).

Meet the author

Adejumoke Ilori is a Commercial and Content Writer for Mother&Baby. She is a mummy of one who's been through the weaning process with her daughter and is able to use her own experiences to help other parents. She enjoys writing about baby world, mothership, true life stories (especially single parenthood), and celebrity gossip. With a degree in Creative Writing, she has also worked with media platforms like, OK! Magazine, New, She Rose Revolution and Fab Magazine.