🌡️ Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin and Rankine instantly
⚡ Common Temperatures
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🌡️ Temperature Reference Points
| Reference Point | Celsius (°C) | Fahrenheit (°F) | Kelvin (K) |
|---|---|---|---|
| Absolute Zero | −273.15 | −459.67 | 0 |
| Dry Ice | −78.5 | −109.3 | 194.65 |
| Water Freezing | 0 | 32 | 273.15 |
| Room Temperature | 20–22 | 68–72 | 293–295 |
| Human Body | 37 | 98.6 | 310.15 |
| Water Boiling | 100 | 212 | 373.15 |
| Oven (baking) | 180 | 356 | 453.15 |
| Iron melting | 1,538 | 2,800 | 1,811 |
Temperature Conversion Formulas
Temperature scales were developed independently and have different zero points and scale intervals. Celsius and Kelvin have the same scale interval — 1°C = 1 K difference — but different zero points. Fahrenheit uses a different scale entirely.
°C → °F
°F = (°C × 9/5) + 32
°F → °C
°C = (°F − 32) × 5/9
°C → K
K = °C + 273.15
K → °C
°C = K − 273.15
°F → K
K = (°F + 459.67) × 5/9
°C → °R
°R = (°C + 273.15) × 9/5
Frequently Asked Questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 (or 1.8), then add 32. Example: 25°C = (25 × 1.8) + 32 = 45 + 32 = 77°F. Quick mental trick: double the Celsius value and add 30 for an approximate answer (e.g. 25°C ≈ 80°F).
What temperature is the same in Celsius and Fahrenheit?
−40° is the only point where Celsius and Fahrenheit are exactly equal: −40°C = −40°F. This is because the two scales converge at this temperature.
What is absolute zero?
Absolute zero is the lowest theoretically possible temperature — 0 Kelvin = −273.15°C = −459.67°F. At this point, molecular motion completely stops. It has never been fully achieved in practice.
Why does the US use Fahrenheit?
The US adopted Fahrenheit in the 18th century before the metric system was widely established. The Fahrenheit scale was defined by Daniel Fahrenheit in 1724 using brine (0°F) and human body temperature (96°F, later corrected). Most other countries switched to Celsius in the 20th century.
What is the Kelvin scale used for?
Kelvin is the SI base unit for temperature and is used in science and engineering, especially thermodynamics, astrophysics, and chemistry. It starts at absolute zero and has the same degree size as Celsius, making it convenient for scientific calculations.
What is normal human body temperature?
The commonly cited normal body temperature is 37°C (98.6°F). However, research shows the average varies between 36.1°C–37.2°C (97°F–99°F) depending on the time of day, age, and measurement location. A fever is generally defined as above 38°C (100.4°F).