Body Temperature Chart — Normal, Fever & Hypothermia Ranges
Last updated: April 23, 2026
A complete reference for human body temperature across age groups and measurement methods, with values in both Celsius (°C) and Fahrenheit (°F). Thresholds follow clinical guidelines from the WHO, CDC, American Academy of Pediatrics, and NHS.
Quick Answer: Normal body temperature: 36.1-37.2°C (97-99°F) · average ~37°C (98.6°F)
At a glance
- Fever (adult): oral ≥ 38°C (100.4°F)
- High fever: 39.5-41°C (103.1-105.8°F) — seek help
- Hypothermia: below 35°C (95°F) — seek help
- Medical emergency: above 41°C (105.8°F) or below 28°C (82.4°F)
Normal Body Temperature
The figure most people know — 37°C or 98.6°F — traces back to German physician Carl Wunderlich's 1851 study of around 25,000 patients and more than a million individual readings. That number became the accepted benchmark for the next 150 years.
Modern research suggests our baseline has drifted lower. A 2020 Stanford study of 677,000 measurements found the current population average sits closer to 36.6°C (97.9°F), with individual "normal" values spanning roughly 36.1 to 37.2°C (97 to 99°F).
Your own normal also shifts through the day. Readings are lowest in the early morning (around 4-6 a.m.) and peak in the late afternoon (around 4-6 p.m.), with a typical swing of 0.5-1°C (0.9-1.8°F). Women also see a small rise of 0.3-0.5°C in the days after ovulation.
Body Temperature Ranges by Category
The table below summarises the full clinical scale, from severe hypothermia through hyperpyrexia. Values are for oral readings in adults unless stated otherwise.
| Category | Celsius (°C) | Fahrenheit (°F) |
|---|---|---|
| Severe hypothermia | < 28.0 | < 82.4 |
| Moderate hypothermia | 28.0-32.0 | 82.4-89.6 |
| Mild hypothermia | 32.0-35.0 | 89.6-95.0 |
| Below normal | 35.0-36.1 | 95.0-97.0 |
| Normal range | 36.1-37.2 | 97.0-99.0 |
| Low-grade fever | 37.3-38.0 | 99.1-100.4 |
| Moderate fever | 38.1-39.4 | 100.5-103.0 |
| High fever | 39.5-41.0 | 103.1-105.8 |
| Hyperpyrexia (emergency) | > 41.0 | > 105.8 |
Cut-offs are approximate clinical conventions and vary slightly between the WHO, CDC, and AAP. Rectal readings run ~0.3°C higher; axillary readings ~0.3°C lower.
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Normal Ranges by Age Group
Baseline body temperature shifts with age. Infants sit a bit higher because of their faster metabolism; older adults often run a little cooler, which can mask a developing fever.
| Age group | Normal (°C) | Normal (°F) |
|---|---|---|
| Newborns (0-3 months) | 36.5-37.5 | 97.7-99.5 |
| Infants (3-12 months) | 36.0-37.4 | 96.8-99.3 |
| Children (1-10 years) | 36.1-37.8 | 97.0-100.0 |
| Adults (11-65 years) | 36.1-37.2 | 97.0-99.0 |
| Older adults (65+) | 35.8-36.9 | 96.4-98.4 |
Temperature by Measurement Method
Where you take the reading changes the number. The core temperature your body regulates is closest to the rectal value; oral, ear, and forehead readings all trend slightly cooler or hotter depending on the site. Approximate equivalents for a healthy adult at 37°C core:
| Method | Typical normal (°C) | Typical normal (°F) |
|---|---|---|
| Rectal (core reference) | 37.0 | 98.6 |
| Oral (under the tongue) | 36.8 | 98.2 |
| Tympanic (ear) | 36.9 | 98.4 |
| Temporal (forehead scanner) | 36.6 | 97.9 |
| Axillary (armpit) | 36.5 | 97.7 |
Axillary readings in particular can run 0.3-0.5°C below core and are generally not used on their own for clinical decisions.
Fever Thresholds in Children
The AAP and NHS define paediatric fever by reading site. Use the lowest applicable threshold when evaluating a sick child.
| Method | Fever starts at (°C) | Fever starts at (°F) |
|---|---|---|
| Rectal (most accurate in infants) | 38.0 | 100.4 |
| Oral | 37.8 | 100.0 |
| Tympanic (ear) | 38.0 | 100.4 |
| Temporal (forehead) | 38.0 | 100.4 |
| Axillary (armpit) | 37.2 | 99.0 |
Factors That Affect Body Temperature
Several normal inputs shift a reading without any illness being present:
- Time of day. Body temperature swings 0.5-1°C between early-morning low and late-afternoon high.
- Physical activity. Vigorous exercise can push core temperature up 1-2°C for a short period.
- Menstrual cycle. A rise of 0.3-0.5°C persists through the luteal phase after ovulation.
- Age. Older adults often run cooler at baseline, which can blunt the fever response.
- Ambient temperature. Hot rooms, hot baths, and heavy clothing skew surface readings upwards.
- Recent food or drink. Hot or cold intake within 15-30 minutes distorts an oral reading.
- Emotional state. Stress and intense emotion can raise readings by a few tenths of a degree.
When to Seek Medical Attention
Use the thresholds below as a guide, not a substitute for clinical judgement. Persistent or worsening symptoms always justify a call to a clinician.
- Adults: fever above 39.4°C (103°F) or any fever lasting more than 3 days.
- Children: fever above 38.9°C (102°F) with lethargy, rash, stiff neck, or difficulty breathing.
- Infants under 3 months: any reading at or above 38.0°C (100.4°F) — contact a clinician the same day.
- Any age — emergency: above 41°C (105.8°F), seizures, confusion, severe headache, or signs of dehydration.
- Hypothermia: reading below 35°C (95°F), shivering, confusion, or slurred speech — seek help immediately.
Common Body Temperature Values (°C → °F)
For exact conversions of specific readings, each of the links below opens a dedicated conversion page:
- Normal range (36.1-37.2°C): 36.5°C, 36.7°C, 37.0°C, 37.1°C, 37.2°C
- Low-grade fever (37.3-38°C): 37.5°C, 37.8°C, 38.0°C
- Moderate fever (38.1-39.4°C): 38.5°C, 39.0°C
- High fever (39.5°C and above): 40.0°C, 41.0°C
Need a different value? Use our Celsius to Fahrenheit converter for any temperature.
How Accurate Is Your Thermometer?
No thermometer is perfect. Technique and device class both matter; a mis-seated ear probe can read a degree off on its own. Rough accuracy figures for the common types:
- Digital oral/rectal. ±0.1°C (±0.2°F). The best blend of accuracy and ease for home use.
- Tympanic (ear). ±0.2°C (±0.4°F), but sensitive to probe fit and earwax. Always use a clean cover and seal the canal.
- Temporal (forehead scanner). ±0.2-0.3°C (±0.4-0.5°F). Fast and contactless, though sweat, cosmetics, and cold skin can skew the reading.
- Axillary (armpit). ±0.3°C, but systematically under-reads core. Screening only.
- Forehead strip thermometers. Unreliable — drift of 0.5-1°C is common. Not recommended for clinical decisions.
- Mercury-in-glass. Historically accurate to ~0.05°C but banned in many countries because of the toxic spill hazard.
For home use, a digital oral (adults) or digital rectal (infants) thermometer is the simplest way to get a trustworthy reading. When in doubt, retake the reading a few minutes later with the same device.
Frequently Asked Questions
What is normal body temperature in Celsius and Fahrenheit?
Normal body temperature is about 37°C (98.6°F) oral, but the healthy range spans 36.1-37.2°C (97-99°F). A 2020 Stanford study found the modern average is slightly lower, around 36.6°C (97.9°F).
At what temperature is a fever considered dangerous?
In adults, a fever above 39.4°C (103°F) warrants medical attention. For infants under 3 months, any reading at or above 38°C (100.4°F) requires immediate evaluation. A temperature above 41°C (105.8°F) at any age is a medical emergency.
What is hypothermia temperature?
Hypothermia occurs when core body temperature drops below 35°C (95°F). Moderate hypothermia is 28-32°C (82.4-89.6°F); severe hypothermia (below 28°C / 82.4°F) can be life-threatening and requires emergency care.
Does body temperature change with age?
Yes. Infants and young children tend to run slightly higher (up to 37.5°C / 99.5°F) due to faster metabolism. Older adults often sit lower (around 36.2°C / 97.2°F), which can make a developing fever harder to spot.
Is 37.5°C considered a fever?
37.5°C (99.5°F) sits at the upper end of normal but is not a clinical fever. Fever is typically defined as an oral temperature at or above 38°C (100.4°F). Readings from 37.3 to 37.9°C (99.1-100.2°F) may be classified as a "low-grade fever" depending on clinical context.
What’s the most accurate way to measure body temperature?
Rectal temperature is the clinical gold standard for core readings, especially in infants. For adults, a digital oral thermometer is accurate and convenient. Tympanic (ear) and temporal (forehead) thermometers are faster but slightly less accurate and more sensitive to technique.
Related Temperature Resources
- All Temperature Converters — calculator, formulas, reference charts
- Celsius to Fahrenheit Converter — convert any temperature value
- Fahrenheit to Celsius Converter
- Celsius to Fahrenheit Conversion Table — full reference chart
- Gas Mark Conversion Chart — oven temperatures (UK/Commonwealth)