At What Body Temperature Should You Go To The Hospital? | ER

Adults: 103°F (39.4°C), or fever with chest pain, confusion, stiff neck, or breathing trouble calls for urgent care.

Your temperature is a clue, not the whole story. A number can be fine in one person and risky in another, based on age, how you measured it, and what else is going on. This guide gives clear cutoffs, plus the warning signs that matter more than the thermometer.

How Body Temperature Numbers Work

Normal body temperature is a range. It shifts through the day, rises after activity, and runs a bit higher later in the day. Your method changes the reading, too.

Where you measure changes the result

• Mouth (oral): Common for adults and older kids.
• Rectal: Often used for infants; close to core temperature.
• Ear: Can be accurate with correct positioning.
• Forehead: Fast, yet it can read low if the skin is cool or sweaty.
• Armpit: Handy for screening, yet it often reads lower than core temperature.

High and low temperatures can both signal danger

People think “hospital” only for high numbers. Low numbers can be just as serious. A core temperature below 95°F (35°C) can point to hypothermia, shock, severe infection, endocrine problems, or medication effects. When low temperature shows up with confusion, weakness, or slow breathing, treat it as an emergency.

At What Body Temperature Should You Go To The Hospital? For Adults, Kids, And Babies

These cutoffs match common clinical guidance. Use them with the person’s symptoms and appearance.

Adults and teens

• Call a clinician if your temperature is 103°F (39.4°C) or higher, even if you can drink and stay alert.
• Go to urgent care or the ER right away if fever comes with chest pain, trouble breathing, severe headache, stiff neck, confusion, seizure, persistent vomiting, or a purple rash.

Mayo Clinic lists 103°F (39.4°C) as a point to contact a clinician for adults and lists the symptom triggers for urgent care. Mayo Clinic fever symptoms and when to seek care is a clear reference.

Babies under 3 months

In newborns, fever can be the only sign of a serious infection.

• Go to emergency care for a rectal temperature of 100.4°F (38°C) or higher.
• Go sooner if the baby is hard to wake, feeding poorly, has a blue or gray tint, or is struggling to breathe.

Babies 3 to 6 months

• Get same-day medical advice for 102°F (38.9°C) or higher.
• Get urgent care for any fever plus poor feeding, limpness, nonstop crying, or breathing trouble.

Kids 6 months to 17 years

With kids, the number matters, yet behavior matters more. A child who is drinking, peeing, and waking up normally can often be watched. A child who is listless or dehydrated needs care sooner.

• Seek urgent care for 104°F (40°C) or higher, or any fever with stiff neck, breathing trouble, seizure, or a rash that doesn’t fade with pressure.
• Get medical advice if fever lasts longer than 3 days, keeps returning, or the child can’t keep fluids down.

If you’re in the UK, the NHS lists when a high temperature needs medical help and what home care is reasonable. NHS guidance on fever in adults includes a symptom checklist that works well for families.

Older adults and people with weak immunity

Some people don’t mount a high fever even with a serious infection. That means you should act on symptoms and duration, not only the number.

• Seek care sooner for fever with shaking chills, new confusion, or dizziness when standing.
• Seek care if the fever stays above 102°F (38.9°C) for more than 48–72 hours.

Next, use the table as a fast sorter when you’re tired or worried.

Temperature reading	Who it applies to	Action that fits the situation
Below 95°F (35°C)	Any age	Emergency care now, especially with confusion or slow breathing.
95–96.8°F (35–36°C) with illness signs	Adults	Same-day evaluation; low temperature plus sickness can be serious.
100.4°F (38°C) or higher (rectal)	Babies under 3 months	ER now; don’t delay.
102°F (38.9°C) or higher	Babies 3–6 months	Same-day medical advice; urgent care if baby looks unwell.
103°F (39.4°C) or higher	Adults and teens	Call a clinician; urgent care if paired with red-flag symptoms.
104°F (40°C) or higher	Kids over 6 months, adults	Urgent care or ER.
105°F (40.6°C) or higher	Any age	ER now.
Any fever plus severe symptoms	Any age	ER now for breathing trouble, seizure, stiff neck, confusion, or severe pain.

Red Flags That Matter More Than The Number

Red flags tell you when risk is high even if the temperature is lower than you expected. If any of these show up, act fast.

Breathing and circulation warnings

• Shortness of breath, noisy breathing, or blue lips
• Chest pressure or pain
• Fainting or a racing heartbeat at rest

Brain and nerve warnings

• New confusion, slurred speech, hard-to-wake sleepiness
• Seizure, new severe headache, or stiff neck
• Weakness on one side or new trouble walking

Dehydration and gut warnings

• Persistent vomiting or can’t keep fluids down
• No urination for 8–10 hours (older kids and adults) or dry diapers for hours in babies
• Severe belly pain or blood in stool

Skin warnings

• A rash that looks purple or like bruising and does not fade with pressure
• Hot, red, painful skin that is spreading fast

Urgent Care Or ER: Picking The Right Door

When you decide to get checked, the next question is where to go. If a person is struggling to breathe, confused, fainting, having chest pain, or having a seizure, skip urgent care and head to the ER or call emergency services. Those settings have rapid labs, imaging, oxygen, and IV medicines on hand.

Urgent care can fit when the person is stable, awake, and breathing comfortably, yet needs an exam the same day. Think of stubborn fever with a sore throat, possible urinary infection symptoms, or dehydration that is mild and improving with sips.

• ER now: any red-flag symptom, temperature below 95°F (35°C), or a baby under 3 months with 100.4°F (38°C) or higher.
• Urgent care: high fever without red flags, symptoms that need testing, or fever that keeps coming back.
• Call your clinic: mild fever with cold symptoms, good hydration, and normal alertness.

Low Body Temperature: When Cold Turns Dangerous

Low temperature can sneak up. Shivering is an early sign, yet severe hypothermia can stop shivering. Confusion can look like “being tired,” so don’t brush it off.

When low temperature means emergency care

• Body temperature below 95°F (35°C)
• Confusion, trouble thinking, or odd behavior
• Slow, shallow breathing or a weak pulse
• Unconsciousness

MedlinePlus treats hypothermia symptoms, especially confusion or problems thinking, as a reason to call emergency services right away. MedlinePlus hypothermia overview and first aid lists the warning signs and first-aid steps.

What to do while help is on the way

• Move the person to a warm, dry place and remove wet clothing.
• Wrap in dry blankets and warm the chest before arms and legs.
• Give warm drinks only if the person is awake and can swallow safely.
• Avoid direct high heat like a heating pad on bare skin.

The CDC’s cold weather guidance warns that hypothermia is a medical emergency and explains steps to prevent and respond to it. CDC hypothermia safety guidance is useful for caregivers.

How To Check Temperature So You Can Trust The Result

Bad readings lead to bad choices. Before you decide “ER or home,” make sure the number is real.

Quick accuracy checklist

• Use the same method each time when you’re tracking a fever.
• Wait 15 minutes after a hot drink, cold drink, smoking, or exercise before oral readings.
• For forehead readings, wipe sweat and let the skin rest for a minute.
• Replace batteries if the screen is dim or the reading jumps around.

When to repeat the reading

Repeat when the result doesn’t match how the person looks. Take two readings a few minutes apart, then go with the higher one if the person seems sick.

Red-flag sign	Why it needs urgent care	What to do next
Breathing trouble or blue lips	Low oxygen can turn dangerous fast	Call emergency services or go to the ER now
Chest pain or pressure	Can signal heart or lung emergencies	ER now
Confusion or hard to wake	Can signal severe infection or low oxygen	ER now; don’t drive alone
Stiff neck with fever	Can signal meningitis	ER now
Seizure	Needs urgent assessment	Emergency care now
Purple rash that doesn’t fade	Can signal serious infection	ER now
Persistent vomiting or no fluids	Dehydration can worsen quickly	Urgent care; ER if weakness or fainting
Temperature below 95°F (35°C)	Hypothermia can slow heart and breathing	Emergency care now

Home Care When There Are No Red Flags

If there are no red flags and the person can drink, pee, and stay alert, home care can be enough for a short stretch.

Steps that help comfort

• Fluids first: water, oral rehydration drinks, broth, or ice pops for kids.
• Light clothing and a comfortable room temperature.
• Rest, then gentle movement to the bathroom to avoid stiffness.
• Fever medicine only as directed on the label and only if it helps comfort.

When to switch from home care to medical care

• Fever that lasts more than 3 days in adults or keeps returning.
• Worsening pain, new rash, new shortness of breath, or increasing weakness.
• Signs of dehydration: dizziness, dark urine, dry mouth, or no tears in a crying child.

Quick Checklist Before You Leave For Care

• Write down the highest temperature, the method used, and the time you took it.
• List medicines taken in the last 24 hours, including cold and flu products.
• Note other symptoms like cough, pain location, rash, vomiting, diarrhea, or burning with urination.
• For kids, note wet diapers or bathroom trips.

A temperature reading can start the decision. If the number crosses the “go now” line, or the person looks seriously unwell, getting checked is the safer move.