Normal Body Temperature for Babies: A Complete Guide for Parents 

Introduction

The normal temperature for babies is usually around 36 to 37°C (96.8 to 98.6°F) and may rise higher, causing a fever which can be due to infections or illnesses. Fever is one of the most common reasons parents seek medical advice for their children, whether during routine visits or emergency consultations¹.

It is natural for parents to feel alarmed when their baby develops a fever. But it’s important to note that mild fluctuations in temperature are common and usually not a cause for concern. However, persistent high or unusually low readings should not be ignored, as they may indicate an underlying condition. Therefore, monitoring your baby’s temperature is important, as it helps distinguish between a mild, self-limiting illness and a potentially serious infection requiring medical attention².

Through this guide, we aim to help you understand when to monitor, when to wait, and when to seek medical care if you notice a change in your baby’s body temperature. 

What Is the Normal Body Temperature for Babies?

As mentioned earlier, a baby’s normal body temperature usually ranges between 36°C and 37°C (96.8 to 98.6°F).  

A fever is defined as a temperature of 38°C (100.4°F) or higher in babies under three months, and 38.5°C (101.3°F) or higher in older children¹.

As a parent/caregiver, it is important to remember that body temperature can naturally vary depending on several factors, such as: 

• The child’s age³ 
• The time of day³ 
• Emotions (e.g., crying, excitement)^1,3 
• Environment (e.g., room temperature, clothing layers)⁴ 
• Sleep or wakefulness³ 
• Physical activity (e.g., running)¹ 
• Illness or infection³ 

Note: Temperature readings may vary slightly depending on the method used (oral, forehead, ear, or rectal)⁴. Therefore, for the most accurate results, a thermometer placed in the rectum is recommended for infants¹.

What Counts as a Fever in Babies?

As discussed above, infant fever is defined as a body temperature of ≥38°C (100.4°F). Based on its intensity, it can be classified as^1,2:

• Low-grade fever: 38 to 38.5°C (100.4 to 101.3°F) 
• High fever: ≥39°C (102.2°F) 

It is crucial to remember that fever is usually a symptom, not a disease, and often indicates that the body’s immune system is responding to certain triggers, such as germs^1,2. Common triggers include¹:

• Infections (viruses or bacteria) such as colds, ear infections, urinary tract infections, gastroenteritis, or childhood illnesses like measles, mumps, chickenpox, etc. 
• Vaccinations (as the body builds immunity). 
• Dehydration, especially with vomiting or diarrhoea. 
• Heat-related issues like sunburn or sunstroke. 
• Recent travel to areas with disease outbreaks (should be reported to a doctor). 
• Other triggers like skin conditions (hives), rare serious illnesses (pneumonia, meningitis, appendicitis), or allergic reactions. 

Note: While fever itself is not always dangerous and the body can often fight it off without medical intervention, it is important for parents to monitor the underlying cause and seek medical care if the baby shows other concerning symptoms. 

Signs and Symptoms of Fever in Babies

Parents can often recognise a fever in a baby just by observing them. Common signs and symptoms include^1,3:

1. Physical signs and symptoms  

• A hot/warm forehead or neck 
• Red or flushed face 
• Sweating or shivering 
• Tired-looking eyes 
• Pale skin 

2. Behavioural signs and symptoms

• Loss of appetite 
• Increased irritability 
• Frequent crying 

Note: If you’re wondering how to know if infant has fever, the most reliable way is by using a thermometer rather than relying on touch. 

When Should Parents Worry About Fever in Babies?

Knowing about fever in babies and when to worry helps parents seek medical care without delay: 

• Under 6 months: Always contact a doctor if the baby’s temperature is 38°C (≥100.4°F), even if there are no other symptoms^1,5,6. 
• 6 months and older: Seek medical advice if the fever rises above 39°C (≥102.2°F)¹.

It is important to seek immediate medical attention if your baby^1,3:

• Experiences a fever that comes and goes (or lasts more than three days) 
• Shows worsening condition since the last medical visit 
• Refuses to drink fluids for a prolonged period 
• Develops a bulging spot on their head 
• Shows signs of being unresponsive, restless, confused, or having a stiff neck 
• Becomes sensitive to light 
• Shows signs of dehydration (e.g., dry mouth/lips, sunken eyes, decreased urine output) 
• Vomits, has diarrhoea, or complains of abdominal pain 
• Has difficulty breathing/swallowing 
• Develops a skin rash 
• Has a febrile seizure 

Important: Never delay seeking medical help if your baby’s fever temperature meets the age-specific thresholds or if any concerning symptoms appear. 

How to Measure Your Baby’s Temperature Safely

A common question is how to know an infant has a fever; the key is to monitor regularly using the right thermometer for their age. 

Parents can choose from different types of thermometers to measure a baby’s temperature: 

• Traditional Glass Thermometer: Can be used orally (for older children), rectally, or under the arm. They require careful handling and longer measurement time^1,7.
• Digital Thermometer: Can be used rectally, underarm, or orally. They are fast and reliable^1,7. 
• Ear (tympanic) Thermometer: Measures infrared radiation from the eardrum; suitable for babies over 6 months. Accuracy may be affected by earwax^1,4.

There are several methods to measure a baby’s temperature, and the choice depends on the baby’s age, comfort, and the level of accuracy needed⁷:

• Rectal (by the bottom/bum) 
• Oral (by mouth) 
• Axillary (under the armpit) 
• Tympanic (in the ear) 

Here is a list of recommended methods by age⁷:

Below is the range of normal body temperature for babies by method⁷:

Stepwise Guide for Taking Your Baby’s Temperature

Follow these step-by-step instructions to measure your baby’s temperature safely and accurately⁷:

1. Rectal 

• Use a digital or traditional rectal thermometer (bulb is larger than oral). 
• Clean with soapy water and rinse. 
• Lubricate the tip with petroleum jelly. 
• Lay your baby on their back with knees bent. 
• Gently insert about 2.5 cm (1 inch) and hold for at least 2 minutes. 
• Remove, read, and clean the thermometer. 

2. Armpit 

• Clean with soapy water and rinse (shake below 36°C (96.8°F) if it is a mercury thermometer). 
• Place in the centre of the armpit (parallel to the body) and hold the arm comfortably. 
• Leave in place for ≥4 minutes. 
• Remove, read, and clean the thermometer. 

3. Ear  

• Use a clean tympanic thermometer. 
• Gently pull the ear up and back. 
• Insert the thermometer to seal the ear canal. 
• Press the button for 1 second, remove it, and read. 

4. Mouth (children ≥5 years) 

• Clean with soapy water and rinse (shake below 36°C (96.8°F) if it is a mercury thermometer). 
• Place under the tongue with the mouth closed for 3 to 4 minutes. 
• Remove, read, and clean. 

Tips 

• Clean the thermometer before and after each use. 
• Do not use a mercury thermometer for children younger than 5 years, as it may break if the child bites down on it. 
• Follow the manufacturer’s instructions for your specific device⁷.

Note: For infants and young children, accuracy is more important than convenience. Always use the most reliable method (typically rectal) to ensure correct temperature measurement. 

Caring for a Baby with Fever (Non-Medication Tips)

Most babies with a fever can be cared for safely at home, as long as there are no signs of a serious illness. The goal is to keep your baby comfortable and well-hydrated. Here are some tips to follow: 

1. Comfort and Clothing

• Dress your baby in light, breathable clothing appropriate for the room temperature. 
• Avoid overdressing, as this can prevent the body from cooling naturally. 
• Keep the room at a comfortable temperature and use a lightweight sheet if needed^6,8.

2. Hydration and Rest

• Encourage your baby to drink plenty of fluids, including breast milk or formula for babies (as advised by the doctor). Keep offering small amounts frequently, even if they are not very thirsty^1,6.
• Allow your baby to rest, but normal play is fine if they feel up to it¹. 

3. Home Comfort Measures

• Use a cool, damp washcloth or sponge soaked in tap water (around 28 to 30°C) to provide comfort. However, avoid bathing to lower the fever, as this mainly cools the skin surface and does not significantly reduce body temperature^3,8.
• Avoid sugary or caffeinated drinks³.
• Keep babies with a fever away from daycare or playgroups to prevent spreading infections, even if they seem well otherwise¹.

Important: If you are considering giving your baby fever-reducing medication, always consult your paediatrician first. Only use doctor-prescribed medications and follow the recommended dosage instructions carefully. 

Conclusion

The normal body temperature in babies generally ranges from 36 to 37°C (96.8 to 98.6°F) and small fluctuations in this range are usually normal. Fever is typically defined as a body temperature of 38°C (100.4°F) or higher and is fairly common in babies and young children. Therefore, careful monitoring is essential to identify when a baby may need medical attention.  

If the fever persists, becomes very high, or is accompanied by concerning symptoms, parents should seek prompt medical advice. Remember, attentive care, reassurance, and gentle observation are the best ways to support your baby. 

Frequently Asked Questions (FAQs)

References

1. InformedHealth.org. Overview: Fever in children [Internet]. Institute for Quality and Efficiency in Health Care (IQWiG); [updated 2022 Dec 9; cited 2025 Sep 9]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279455/ 

2. World Health Organization. Pocket book of hospital care for children: guidelines for the management of common childhood illnesses [Internet]. World Health Organization; [cited 2025 Sep 9]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK154436/ 

3. The Sydney Children’s Hospitals Network. Fever factsheet [Internet]. NSW Government; [cited 2025 Sep 9]. Available from: https://www.schn.health.nsw.gov.au/fever-factsheet 

4. Temperature measurement in paediatrics. Paediatr Child Health. 2000 Jul;5(5):273-84. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC2819918/ 

5. World Health Organization. The management of fever in young children with acute respiratory infections in developing countries [Internet]. WHO; [cited 2025 Sep 9]. Available from: https://iris.who.int/bitstream/handle/10665/58266/WHO_ARI_93.30.pdf 

6. NIDirect. Fever in children [Internet]. nidirect; [cited 2025 Sep 9]. Available from: https://www.nidirect.gov.uk/conditions/fever-children 

7. How to take a child’s temperature. Paediatr Child Health. 2000 Jul;5(5):277-87. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC2819919/ 

8. Indian Academy of Pediatrics. IAP Parent Guidelines Committee. Guidelines for Fever: General Management [Internet]. Indian Academy of Pediatrics; [cited 2025 Sep 9]. Available from: https://iapindia.org/pdf/IAP-Guidelines-for-Fever.pdf 

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