Fever Temperature Calculator
Classify a body temperature reading as normal, low-grade fever, moderate fever, or high fever.
Supports both Celsius and Fahrenheit, with age-based guidance.
Understanding Body Temperature and Fever
Normal body temperature is often cited as 37°C (98.6°F), but this is an average. A healthy range is typically 36.1°C to 37.2°C (97°F to 99°F). Body temperature also varies throughout the day — it is lowest in the morning and highest in the late afternoon.
Temperature Conversion
Celsius to Fahrenheit: °F = (°C × 9/5) + 32 Fahrenheit to Celsius: °C = (°F − 32) × 5/9
Fever Classification (Adults)
| Temperature | Classification |
|---|---|
| Below 36.1°C (97°F) | Hypothermia (below normal) |
| 36.1°C – 37.2°C (97°F – 99°F) | Normal |
| 37.3°C – 38.0°C (99.1°F – 100.4°F) | Low-grade fever |
| 38.1°C – 39.0°C (100.5°F – 102.2°F) | Moderate fever |
| 39.1°C – 40.0°C (102.3°F – 104.0°F) | High fever |
| Above 40.0°C (104°F) | Very high fever — seek medical attention |
Age-Specific Guidance
Infants (under 3 months): Any temperature of 38.0°C (100.4°F) or higher is a medical emergency. Seek immediate medical attention.
Infants 3–6 months: Consult a doctor for any fever of 38.0°C (100.4°F) or above.
Children 6 months to 2 years: Contact a doctor if fever is above 39°C (102°F) or lasts more than 24 hours.
Children 2+ and Adults: Low-grade fevers often resolve on their own. Seek care if fever is above 39.4°C (103°F), lasts more than 3 days, or is accompanied by severe symptoms.
When to Seek Immediate Help
- Any fever in a baby under 3 months old
- Temperature above 40°C (104°F) in anyone
- Fever with stiff neck, confusion, or rash
- Fever after returning from travel to a tropical region
Disclaimer: This tool is for general information only. Always consult a healthcare professional for medical advice about fever management.