100.4 Fahrenheit to Celsius
100.4 °F = 38 °C
100.4 degrees Fahrenheit equals 38 degrees Celsius.
How to convert 100.4 °F to °C
Use the formula °C = (°F − 32) × 5/9:
°C = (100.4 − 32) × 5/9°C = 68.4 × 5/9°C = 38
So 100.4 °F = 38 °C.
Rounded values and quick estimate
- Rounded to a whole number: 38 °C
- Rounded to one decimal place: 38 °C
Quick mental estimate: subtract 30 and halve it. For 100.4 °F that gives about 35.2 °C — off by 2.8 °C (7.4%). Use the exact formula when precision matters.
100.4 Fahrenheit in other units
100.4 °F (38 °C) is the threshold most doctors use to define a fever for rectal, ear and forehead readings.
A body temperature of 38 °C (100.4 °F) or higher is commonly used as the threshold for a fever.
38 °C falls in the range used for human body temperature. As air temperature it is extreme heat. As a body reading, about 36.1–37.2 °C is typical for healthy adults, 38 °C (100.4 °F) and above is commonly considered a fever, and below 35 °C (95 °F) is considered hypothermia.
- Celsius
- 38 °C
- Degrees Réaumur
- 30.4 °Ré
- Degrees Delisle
- 93 °De
- Degrees Newton
- 12.54 °N
- Degrees Rømer
- 27.45 °Rø
- Kelvin
- 311.15 K
- Rankine
- 560.07 °R
General information only, not medical advice. If you are concerned about a temperature reading, contact a healthcare professional.
100.4 °F and nearby values
| Fahrenheit | Celsius |
|---|---|
| 100 °F | 37.78 °C |
| 100.1 °F | 37.83 °C |
| 100.2 °F | 37.89 °C |
| 100.3 °F | 37.94 °C |
| 100.4 °F | 38 °C |
| 100.5 °F | 38.06 °C |
| 100.6 °F | 38.11 °C |
| 100.7 °F | 38.17 °C |
| 100.8 °F | 38.22 °C |
About fahrenheit and celsius
The Fahrenheit scale puts water’s freezing point at 32 °F and boiling point at 212 °F. It is the everyday temperature scale in the United States.
The Celsius scale sets the freezing point of water at 0 °C and its boiling point at 100 °C (at sea level). It is used for everyday temperatures in almost every country.
Related conversions
Frequently asked questions
What is 100.4 Fahrenheit in Celsius?
100.4 degrees Fahrenheit is 38 degrees Celsius (100.4 °F = 38 °C).
How do you convert 100.4 °F to °C?
Apply °C = (°F − 32) × 5/9: °C = (100.4 − 32) × 5/9, °C = 68.4 × 5/9, °C = 38.
How many degrees Fahrenheit is 38 °C?
38 °C is about 100.4 degrees Fahrenheit.
Is 100.4 °F a fever?
Yes — 100.4 °F (38 °C) or higher is generally considered a fever. For babies under 3 months, call a doctor.