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Convert body temperature between Fahrenheit and Celsius with instant fever assessment. Check if a temperature reading indicates a normal, low-grade, or high fever.
Converted Temperature
37.0°C
Normal
98.6°F = 37.0°C
| °F | °C | Status | Notes |
|---|---|---|---|
| 95.0°F | 35.0°C | Hypothermia | Medical emergency threshold |
| 96.0°F | 35.6°C | Below Normal | May indicate hypothermia risk |
| 97.0°F | 36.1°C | Normal (low end) | Typical early morning temperature |
| 97.7°F | 36.5°C | Normal | Typical resting temperature |
| 98.2°F | 36.8°C | Normal | Updated average body temperature |
| 98.6°F | 37.0°C | Normal (classic avg) | Traditional "normal" body temperature |
| 99.0°F | 37.2°C | Normal (high end) | Typical late afternoon temperature |
| 99.5°F | 37.5°C | Low-Grade Fever | Mildly elevated, monitor closely |
| 100.0°F | 37.8°C | Low-Grade Fever | Body may be fighting mild infection |
| 100.4°F | 38.0°C | Fever | Clinical fever threshold |
| 101.0°F | 38.3°C | Fever | Common with flu and infections |
| 101.5°F | 38.6°C | Fever | Rest and fluids recommended |
| 102.0°F | 38.9°C | Fever | Consider fever-reducing medication |
| 103.0°F | 39.4°C | High Fever | Seek medical attention |
| 104.0°F | 40.0°C | High Fever | Urgent medical attention needed |
| 105.0°F | 40.6°C | Dangerous | Emergency medical care required |
| 106.0°F | 41.1°C | Life-Threatening | Risk of organ damage, call 911 |
A fever is a temporary increase in body temperature above the normal range, typically defined as a reading of 100.4°F (38.0°C) or higher. Fever is not an illness itself but rather a symptom and a natural defense mechanism. When the body detects an infection from bacteria, viruses, or other pathogens, the hypothalamus in the brain raises the body's temperature set point. This elevated temperature helps activate the immune system and creates a less favorable environment for many pathogens.
The traditional "normal" body temperature of 98.6°F (37.0°C) was established by German physician Carl Reinhold August Wunderlich in 1868 based on over a million measurements. However, modern research suggests the average body temperature has decreased slightly over the past century and is closer to 97.5–98.2°F (36.4–36.8°C). Individual normal temperatures vary, and factors like time of day, physical activity, hormonal cycles, and age all influence baseline temperature.
Understanding the difference between Fahrenheit and Celsius temperature scales is crucial for accurate fever assessment, especially when traveling internationally or using medical devices calibrated in different units. Most countries outside the United States use Celsius for medical temperature measurement, while the U.S. predominantly uses Fahrenheit. Being able to quickly convert between the two can be important in medical situations.
°C = (100.4 − 32) × 5/9
°C = 68.4 × 0.5556
°C = 38.0°C — This is the clinical fever threshold
°F = (39.0 × 9/5) + 32
°F = 70.2 + 32
°F = 102.2°F — This indicates a moderate fever
°C = (98.6 − 32) × 5/9
°C = 66.6 × 0.5556
°C = 37.0°C — Classic normal body temperature
For a rough F-to-C conversion in the body temperature range: subtract 32, then divide by 2. Example: 102°F − 32 = 70, divided by 2 = 35. The actual answer is 38.9°C, so add about 3–4 degrees to your rough estimate for body temps.
| Range (°F) | Range (°C) | Status | Action |
|---|---|---|---|
| 97.0–99.5 | 36.1–37.5 | Normal | No action needed |
| 99.5–100.3 | 37.5–37.9 | Elevated | Monitor closely, dress lightly |
| ≥ 100.4 | ≥ 38.0 | Fever | Contact pediatrician immediately (under 3 months: ER) |
| Range (°F) | Range (°C) | Status | Action |
|---|---|---|---|
| 97.0–99.0 | 36.1–37.2 | Normal | No action needed |
| 99.1–100.3 | 37.3–37.9 | Low-Grade Fever | Rest, fluids, monitor |
| 100.4–102.0 | 38.0–38.9 | Fever | Fever reducers, fluids, rest |
| ≥ 102.2 | ≥ 39.0 | High Fever | Contact doctor |
| Range (°F) | Range (°C) | Status | Action |
|---|---|---|---|
| 97.0–99.0 | 36.1–37.2 | Normal | No action needed |
| 99.1–100.3 | 37.3–37.9 | Low-Grade Fever | Monitor, rest, stay hydrated |
| 100.4–103.0 | 38.0–39.4 | Fever | Rest, fluids, OTC fever reducers |
| ≥ 103.0 | ≥ 39.4 | High Fever | Seek medical attention |
| ≥ 105.0 | ≥ 40.6 | Emergency | Call 911 immediately |
Temperature changes are often the first sign of infection. Regular monitoring helps detect illness early when treatment is most effective.
Infants and young children are more vulnerable to fevers. Accurate temperature conversion helps parents assess severity and respond appropriately.
Different countries use different temperature scales. Converting between F and C is essential for understanding medical advice while traveling abroad.
Accurately reporting temperature to healthcare providers requires knowing the correct value in the right scale. Misreported temperatures can affect diagnosis.
Body temperature naturally varies by up to 1°F throughout the day. For consistent tracking, measure at the same time each day, ideally in the morning before activity.
Rectal readings are about 0.5–1.0°F higher than oral, while armpit readings are 0.5–1.0°F lower. Adjust your assessment based on where the temperature was taken.
Wait at least 15–30 minutes after eating, drinking, or exercising before taking an oral temperature for the most accurate reading.
Individual baseline temperatures vary. Some people normally run at 97.5°F while others are at 99.0°F. Know your own baseline for accurate assessment.
A low-grade fever lasting more than a few days may indicate a chronic infection or other condition that needs medical evaluation, even if the temperature seems mild.
Touching the forehead is unreliable for determining fever. Always use a thermometer for accurate measurement, especially for children and infants.
A temperature of 100.4 degrees Fahrenheit (38.0 degrees Celsius) or higher is generally considered a fever for adults. For infants under 3 months, any temperature of 100.4 F or higher requires immediate medical attention.
Normal body temperature ranges from 97.0 to 99.0 degrees Fahrenheit (36.1 to 37.2 degrees Celsius) for most adults. The commonly cited 98.6 F (37.0 C) is an average, and individual baseline temperatures can vary.
To convert Fahrenheit to Celsius, subtract 32 from the Fahrenheit temperature, then multiply by 5/9. For example, 100.4 F minus 32 equals 68.4, times 5/9 equals 38.0 C.
To convert Celsius to Fahrenheit, multiply the Celsius temperature by 9/5, then add 32. For example, 38.0 C times 9/5 equals 68.4, plus 32 equals 100.4 F.
A low-grade fever is a body temperature between 99.1 and 100.3 degrees Fahrenheit (37.3 to 37.9 degrees Celsius). It is slightly above normal but below the clinical fever threshold and may indicate the body is fighting a mild infection.
Seek immediate medical attention if a fever reaches 103 F (39.4 C) or higher in adults, 100.4 F (38 C) or higher in infants under 3 months, or if the fever persists for more than three days. Also seek help if the fever is accompanied by severe symptoms like difficulty breathing, confusion, or persistent vomiting.
Yes, measurement location significantly affects readings. Rectal temperatures are typically 0.5 to 1.0 F higher than oral. Axillary (armpit) readings are about 0.5 to 1.0 F lower than oral. Tympanic (ear) and temporal (forehead) readings can vary based on technique and device.
Body temperature follows a circadian rhythm, typically lowest in the early morning (around 4 AM) and highest in the late afternoon (around 4 to 6 PM). This variation can be 1.0 F (0.6 C) or more. Exercise, food intake, hormonal changes, and ambient temperature also cause fluctuations.
A temperature of 99 F (37.2 C) is at the upper end of the normal range and is not typically classified as a fever. It may be considered a low-grade fever by some definitions, particularly if it is above the individual normal baseline temperature.
Hypothermia occurs when body temperature drops below 95.0 F (35.0 C). It is a medical emergency that can cause confusion, drowsiness, loss of coordination, and in severe cases, cardiac arrest. Hypothermia most commonly results from prolonged exposure to cold temperatures.
This tool is for educational and informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical concerns. If you or someone you know has a high fever or medical emergency, contact your doctor or call emergency services immediately.