Body Temperature Converter
Convert a thermometer reading between °C and °F and check it against commonly used fever thresholds. The threshold depends on where the temperature was taken — an armpit reading runs lower than a rectal one.
How to use the Body Temperature Converter
- Enter the reading and choose °C or °F.
- Select where it was measured (mouth, rectal, ear, forehead or armpit).
- Choose the age group to see age-specific guidance.
How it works
The conversion uses °F = °C × 9/5 + 32. Fever thresholds commonly used by health organizations are:
- Rectal, ear or forehead: 38.0 °C (100.4 °F) or higher
- Oral (mouth): 37.8 °C (100 °F) or higher
- Armpit: 37.2 °C (99 °F) or higher
Normal body temperature varies by person, time of day and measurement site; 37 °C (98.6 °F) is a traditional average, but readings from about 36.1 °C to 37.2 °C (97 °F to 99 °F) are typical for healthy adults. This tool is for information only and is not medical advice.
Body temperature chart (oral reading, adults)
| °C | °F | Meaning |
|---|---|---|
| 35 | 95 | Below 35 °C: hypothermia |
| 36 | 96.8 | Normal (lower range) |
| 36.5 | 97.7 | Normal |
| 37 | 98.6 | Normal |
| 37.5 | 99.5 | Normal to slightly raised |
| 37.8 | 100 | Fever (oral threshold) |
| 38 | 100.4 | Fever |
| 38.5 | 101.3 | Fever |
| 39 | 102.2 | Fever |
| 39.4 | 102.9 | High fever — contact a doctor |
| 40 | 104 | High fever |
| 41.1 | 106 | Very high — emergency |
Frequently asked questions
Is 37.5 °C a fever?
Usually not. 37.5 °C (99.5 °F) is below the common fever thresholds of 37.8 °C oral and 38 °C rectal or ear. It is above 37.2 °C, so an armpit reading of 37.5 °C would count as a low-grade fever.
What is 38 °C in Fahrenheit?
38 °C is 100.4 °F, the most commonly used fever threshold.
Which thermometer reading is most accurate?
Rectal readings are the most accurate for babies and young children; oral readings are reliable for older children and adults. Armpit readings are the least accurate.