What to Do If Your Baby Has a Fever: A Guide

What if the thermometer number matters less than your baby’s age and how they’re acting? When you’re wondering what to do if baby has a fever, it’s understandable to feel worried and unsure where to start.

Take a breath. A temperature of 100.4°F (38°C) or higher in a baby younger than 3 months needs immediate medical attention, while an older baby’s comfort, behavior, and other symptoms can help guide what to do next. I find it helpful to focus on those clear next steps rather than trying to figure everything out at once. If your baby has trouble breathing, is hard to wake, or seems seriously unwell, seek urgent medical care.

This guide will help you check your baby’s temperature, spot warning signs, offer safe comfort, and know when to call a clinician. We’ll walk through the next steps calmly, so you can focus on your baby and make a more confident plan.

Baby Fever: Start With Age and Symptoms

Quick answer: Check your baby’s age, temperature, overall appearance, and any urgent symptoms. If your baby is younger than 3 months and has a rectal temperature of 100.4°F (38°C) or higher, contact a clinician immediately or go to an emergency department.

A fever is a sign that something may be going on, not a diagnosis by itself. As you think about what to do if baby has a fever, look at the whole picture, not only the thermometer. A baby who is breathing comfortably and responding as usual may seem different from one who is unusually hard to wake or struggling to breathe.

Which temperature counts as a fever in a baby?

A rectal temperature of 100.4°F (38°C) or higher counts as a fever, according to the American Academy of Pediatrics. For babies under 3 months, rectal measurement is the most accurate method, but ask your clinician for guidance if you’re unsure how to take it.

Readings can differ depending on where and how you measure. Don’t try to guess what one method’s reading would be with another, or casually add or subtract degrees. Note the number and the method you used, then share both with your clinician. For background on what is a fever, you can read about fever as a body response; that context doesn’t replace advice about your baby’s symptoms.

Why your baby’s age and behavior matter

Age changes how quickly a fever needs medical attention. For a baby younger than 3 months, a rectal temperature at or above 100.4°F (38°C) needs prompt assessment, even if your little one otherwise seems well. Don’t wait to see whether the fever goes away before calling.

For older babies, notice how they’re acting compared with usual. Are they making eye contact, waking and responding, feeding, and breathing comfortably? A change in any of these can be useful information for the clinician. Trust your concern if your baby seems seriously unwell.

• Seek urgent care now for difficulty breathing, unusual unresponsiveness, or another severe symptom.
• Call a clinician promptly if you’re worried about your baby’s behavior, feeding, or condition, even if the temperature is below the fever threshold.
• For a baby under 3 months, call immediately for a rectal temperature of 100.4°F (38°C) or higher.

When you’re unsure, it’s okay to call and describe what you’re seeing. A qualified clinician can help you decide on the safest next step.

Baby fever warning signs: when to seek urgent medical care

Quick answer: Get emergency help for severe breathing trouble, a seizure, blue or gray skin, or if your baby is very difficult to wake. Don’t wait for the temperature to rise or fall before acting.

Fever is only one part of the picture. If your baby has a severe or rapidly worsening symptom, call your local emergency number or go to emergency care. The American Academy of Pediatrics’ Fever and Your Baby guidance can help you understand fever-related warning signs, but it shouldn’t delay urgent care when your baby appears seriously unwell.

Symptoms that need emergency attention

Seek emergency help now if your baby has any of these signs, whether or not you’ve confirmed a fever:

• Severe trouble breathing, such as struggling for each breath or being unable to breathe comfortably.
• A seizure, especially if it’s happening now, or your baby doesn’t respond normally afterward.
• Blue or gray coloring around the lips, face, or skin.
• Unusual unresponsiveness, such as being very hard to wake or not reacting as usual.
• A concerning rash, particularly purple spots, or a stiff neck.
• Possible severe dehydration, such as no wet diapers or a sunken soft spot, especially alongside unusual sleepiness or weakness.

A brief moment of smiling or settling doesn’t rule out a serious problem. If symptoms are severe or quickly getting worse, trust what you’re seeing and get help rather than waiting to recheck the temperature.

When a young baby’s fever needs a prompt call

For a baby younger than 3 months, a rectal temperature of 100.4°F (38°C) or higher needs immediate medical assessment. Call your baby’s clinician right away or go to an emergency department, even if your baby seems fairly well. Don’t wait to try home care first.

For babies ages 3 to 6 months, contact the pediatrician for a temperature of 101°F (38.3°C) or higher, or for any fever that comes with unusual irritability, sluggishness, or discomfort. For babies older than 6 months, call for a temperature of 103°F (39.4°C) or higher, a fever that lasts more than 24 hours in a child younger than 2, or a temperature that rises above 104°F (40°C) repeatedly. If you’re weighing what to do if baby has a fever, age and symptoms help guide how soon to seek care, but a clinician can advise you about your baby’s situation.

Once urgent concerns are addressed, you can browse our baby and family product buying guides for general parenting essentials. These guides aren’t a substitute for medical care and don’t treat fever.

How to check your baby’s temperature and understand the reading

Quick answer: Use a digital thermometer that’s suitable for your baby’s age, follow its instructions, and write down the reading, time, and method. If your baby has an urgent warning sign, get medical help rather than delaying to take another measurement.

Touch can tell you your baby feels warm, but it can’t confirm or rule out a fever. A thermometer gives you a clearer reading to share with a clinician. The American Academy of Pediatrics explains temperature-taking methods for infants in its Fever and Your Baby guidance.

Choosing and using a thermometer safely

For babies younger than 3 months, a rectal temperature is the most accurate way to check for fever. A forehead thermometer may be another option, while ear thermometers aren’t recommended for babies under 6 months. If you’re unsure which method to use, ask your baby’s clinician.

Use a digital thermometer and follow the device instructions for the chosen method. If taking a rectal temperature feels unfamiliar, ask a clinician to show you how to do it safely. Don’t use a thermometer in a way the manufacturer doesn’t recommend, and don’t compare readings from different methods as though they were interchangeable.

Temperature thresholds can vary by measurement method. Record the number exactly as displayed and note how you took it. Avoid trying to convert it by adding or subtracting a degree. If the reading is concerning for your baby’s age, contact a clinician for guidance.

What to track before you call the pediatrician

A few clear notes can make a call easier, especially when you’re tired or worried. Jot down:

• Your baby’s age and the temperature reading.
• The time you took it and the thermometer method used.
• How your baby is feeding, how many wet diapers you’ve noticed, and any changes in behavior.
• Other symptoms, such as a cough, rash, vomiting, or breathing changes.
• Any medicine given, including the amount and time.

These details help the clinician understand what’s happening and advise you on the next step. If you’re figuring out what to do if baby has a fever and your baby seems seriously unwell, don’t wait to complete your notes or repeat a reading. Seek urgent help first, then share what you know.

What to Do at Home When Your Baby Has a Fever

Quick answer: Keep your baby comfortable, continue age-appropriate feeding, and watch for changes in breathing, alertness, and wet diapers. Home comfort steps don’t replace prompt medical advice when your baby’s age or symptoms call for it.

The goal is to help your baby feel settled, not to force the thermometer reading back to normal. If your baby is younger than 3 months and has a rectal temperature of 100.4°F (38°C) or higher, contact a clinician immediately rather than starting with home care.

Comfort measures that may help your baby feel settled

Offer breast milk or formula as usual for an infant, and follow your clinician’s advice about fluids for your baby’s age. Dress your baby in lightweight, comfortable clothing and keep the room at a comfortable temperature. Don’t bundle them in extra layers to “sweat out” a fever.

Watch how often your baby feeds and has wet diapers. A dry mouth, fewer wet diapers than usual, or a sunken soft spot can be signs of dehydration. Contact a clinician promptly if you notice these changes, or if your baby is too sleepy or unwell to feed. The American Academy of Pediatrics’ guidance on fever in babies can help you understand when to seek medical advice.

Avoid cold baths and alcohol rubs. They can make your baby uncomfortable and aren’t a safe way to manage a fever. If a bath or wipe-down causes shivering, stop.

Fever medicine: what parents should check first

Fever medicine may ease discomfort, but the right choice depends on your baby’s age and weight. Ask a clinician before giving acetaminophen to a baby younger than 3 months. AAP guidance on ibuprofen says not to give it to babies younger than 6 months unless a doctor directs you.

• Follow the product label or a clinician’s directions for the correct medicine and amount. Doses for infants are based on weight, so ask your pediatrician or pharmacist for your baby’s dose, and don’t guess.
• Measure in milliliters (mL) with the syringe or dropper that comes with the medicine, never a kitchen spoon. Use only infant or children’s products, never adult-strength medicine, and avoid combination cold or flu products.
• Don’t combine or alternate fever medicines unless your clinician recommends it.
• MedlinePlus explains the link between aspirin and Reye syndrome, a rare but serious condition. Don’t give aspirin to a child or teenager unless a clinician specifically directs you.

If you’re unsure what to do if baby has a fever, call your pediatrician before giving medicine. For general baby-care and family product ideas, explore our parenting product buying guide. Products don’t treat a fever or replace medical care.

Calling the pediatrician about baby fever: what to say and what happens next

Quick answer: Call promptly if your baby is under 3 months and has a rectal temperature of 100.4°F (38°C) or higher, if an age-based fever guideline applies, or if you’re worried about your baby’s condition. For severe or rapidly worsening symptoms, use local emergency services instead of waiting for a call back.

It can be hard to think clearly when your baby isn’t feeling well. A few notes can help you explain what you’re seeing and understand the next step. The American Academy of Pediatrics’ Fever and Your Baby guidance also outlines when parents should contact a doctor.

How to prepare for a fever-related call

Share the details you have. You don’t need to wait until every item is written down before calling, especially if your baby is very young or seems seriously unwell.

• Your baby’s age and temperature reading.
• How and when you measured the temperature.
• Symptoms, including changes in breathing, alertness, or responsiveness.
• How your baby is feeding and whether wet diapers are less frequent than usual.
• Any medicine given, including the name, amount, and time.

Then ask what to do next: Should your baby be seen? What should you watch for? If medicine is appropriate, what product and amount should you use for your baby’s age and weight? Ask when to call again or seek urgent care if things change.

Following medical advice and monitoring changes

The clinician may ask questions, recommend an examination, or give instructions for care and monitoring. The next step depends on your baby’s age, symptoms, and the details you share, so follow the guidance given for your child rather than a general online schedule.

Keep watching your baby’s breathing, responsiveness, feeding, and wet diapers. If symptoms worsen or a new urgent warning sign appears, seek help promptly. For severe breathing trouble, a seizure, blue or gray coloring, or difficulty waking, contact local emergency services or go to emergency care.

If you’re unsure what to do if baby has a fever, calling the pediatrician is a reasonable step. You know your baby’s usual behavior, and it’s okay to ask for help when something feels wrong. For general family and baby product ideas unrelated to treating illness, explore our baby buyers’ guide.

Take the Next Step With Confidence

Knowing what to do if baby has a fever starts with three things: your baby’s age, an accurate temperature reading, and how your little one is acting. A rectal temperature of 100.4°F (38°C) or higher in a baby younger than 3 months needs immediate medical attention. Severe breathing trouble, a seizure, unusual unresponsiveness, or other serious symptoms also call for urgent help.

For other situations, keep your baby comfortable, continue age-appropriate feeding, and note changes in symptoms, wet diapers, and behavior. When you call the pediatrician, sharing the temperature, measurement method, timing, and any medicine given can help the clinician advise you. Don’t hesitate to reach out if you’re worried. You know your baby, and asking for guidance is a caring next step.

For general parenting and baby product ideas, explore our baby buyers’ guide. It’s separate from medical advice, which should come from your baby’s clinician. You’re doing your best, one calm step at a time.

Frequently Asked Questions

What temperature is considered a fever in a baby?

A rectal temperature of 100.4°F (38°C) or higher is considered a fever. The threshold can vary by measurement method, so note how you took your baby’s temperature instead of trying to convert the reading. For babies younger than 3 months, rectal measurement is the most accurate method. The American Academy of Pediatrics explains infant fever thresholds and next steps in its guidance on fever in babies.

Should I call the doctor if my newborn has a fever?

Yes. If your baby is younger than 3 months and has a rectal temperature of 100.4°F (38°C) or higher, contact a clinician immediately or go to an emergency department. Don’t wait to see if the temperature comes down, even if your baby seems fairly well. Very young babies need prompt medical assessment. If you’re unsure how the temperature was taken, call and tell the clinician the reading and method.

Can teething cause a fever in babies?

Teething may cause a slight rise in temperature, but it doesn’t cause a true fever. A rectal temperature of 100.4°F (38°C) or higher shouldn’t be assumed to be from teething. Consider your baby’s age and overall behavior, including feeding, alertness, and breathing. Contact a clinician if you’re concerned or notice other symptoms. If your baby is younger than 3 months, follow the urgent fever guidance and call promptly.

How should I take my baby’s temperature?

Use a digital thermometer and follow its instructions. For babies younger than 3 months, a rectal reading is the most accurate; ask a clinician to show you how if you’re unsure. Ear thermometers aren’t recommended for babies under 6 months. Record the number, time, and method used, since readings can vary by method. Don’t rely on touch alone to confirm or rule out fever, and don’t delay urgent care to repeat a measurement.

Can I give my baby medicine for a fever?

Ask a clinician before giving fever medicine to a young baby. Don’t give acetaminophen to an infant under 3 months unless a doctor instructs you, and don’t give ibuprofen to babies younger than 6 months. For an older baby, ask which medicine and amount are right for your child’s age and weight, and follow the product label or clinician’s directions. Don’t give aspirin or combine or alternate medicines unless a clinician advises it.

What should I do if my baby has a fever but seems fine?

Consider your baby’s age even if they seem comfortable. If your baby is younger than 3 months and has a rectal temperature of 100.4°F (38°C) or higher, contact a clinician immediately. For an older baby, keep an eye on feeding, breathing, alertness, and wet diapers, and follow age-based advice about when to call. If you’re unsure what to do if baby has a fever, it’s appropriate to call your pediatrician for guidance.

When should I take my baby to the emergency room for a fever?

Seek emergency care for severe breathing trouble, a seizure, blue or gray coloring, difficulty waking, or another severe or rapidly worsening symptom. A purple rash, stiff neck, or signs of serious dehydration, such as no wet diapers or a sunken soft spot, also need urgent attention. For a baby younger than 3 months with a rectal temperature of 100.4°F (38°C) or higher, contact a clinician immediately or go to an emergency department.