Quick Answer
To convert Celsius to Fahrenheit, use °F = (°C × 9/5) + 32. To convert Fahrenheit to Celsius, use °C = (°F − 32) × 5/9. Kelvin equals Celsius plus 273.15.
What Is a Temperature Converter?
Temperature conversion is unique among unit conversions because the common scales — Celsius, Fahrenheit, and Kelvin — don't just use different unit sizes, they also have different zero points. This means converting between them requires both multiplication and addition/subtraction, unlike length or weight conversions, which are pure multiplication.
Celsius (°C) is used by most of the world and the scientific community, with water freezing at 0°C and boiling at 100°C. Fahrenheit (°F) is used primarily in the United States, with water freezing at 32°F and boiling at 212°F. Kelvin (K) is the scientific absolute temperature scale, where 0 K represents absolute zero — the theoretical point where molecular motion stops entirely — making it essential for physics and chemistry calculations.
Understanding the relationship between these scales matters for international travel, cooking with foreign recipes, interpreting weather reports while traveling, scientific work, and engineering applications where the correct scale is critical for safety and accuracy.
How to Use This Temperature Converter
- 1Select the temperature scale you're converting from (Celsius, Fahrenheit, or Kelvin).
- 2Select the scale you're converting to.
- 3Enter the temperature value.
- 4The calculator instantly returns the converted value.
The Formula Explained
°F = (°C × 9/5) + 32°C = (°F − 32) × 5/9K = °C + 273.15Example: Converting 37°C (normal human body temperature) to Fahrenheit
- °C = 37
- °F = (37 × 9/5) + 32
- °F = 66.6 + 32
Tips & Things to Know
- A useful mental shortcut for rough Celsius-to-Fahrenheit conversion: double the Celsius value and add 30 (this approximation is reasonably close for everyday temperatures, though not exact).
- Never apply a simple multiplication factor alone for temperature — always include the offset (+32 or −32) or the result will be significantly wrong, unlike most other unit conversions.
- Kelvin is never expressed as a negative number in standard physics, since 0 K is absolute zero — if a Kelvin conversion produces a negative result, double-check the input or formula direction.
- When traveling or following recipes from a country using a different scale, keep a quick reference for common temperatures (body temperature, room temperature, oven baking temperatures) in both scales.