Temperature Converter – Convert Celsius, Fahrenheit & Kelvin Online
Temperature Converter
Temperature Conversion Formulas
| Conversion | Formula |
|---|---|
| Celsius to Fahrenheit | (°C × 9/5) + 32 |
| Fahrenheit to Celsius | (°F − 32) × 5/9 |
| Celsius to Kelvin | °C + 273.15 |
| Kelvin to Celsius | K − 273.15 |
What is a Temperature Converter?
A temperature converter is an online tool that instantly converts temperature values between Celsius (°C), Fahrenheit (°F), and Kelvin (K). Different countries and scientific fields use different temperature scales, which can cause confusion when reading international weather forecasts, cooking recipes, science textbooks, or medical references. This converter eliminates that confusion by giving you the equivalent value in any unit in a single click.
Temperature Conversion Formulas with Examples
| Conversion | Formula | Example |
|---|---|---|
| Celsius to Fahrenheit | °F = (°C × 9/5) + 32 | 100°C → 212°F |
| Fahrenheit to Celsius | °C = (°F − 32) × 5/9 | 98.6°F → 37°C |
| Celsius to Kelvin | K = °C + 273.15 | 0°C → 273.15 K |
| Kelvin to Celsius | °C = K − 273.15 | 373.15 K → 100°C |
| Fahrenheit to Kelvin | K = (°F + 459.67) × 5/9 | 32°F → 273.15 K |
| Kelvin to Fahrenheit | °F = (K × 9/5) − 459.67 | 300 K → 80.33°F |
Common Temperature Reference Points
| Reference Point | Celsius (°C) | Fahrenheit (°F) | Kelvin (K) |
|---|---|---|---|
| Absolute Zero | −273.15°C | −459.67°F | 0 K |
| Water Freezes | 0°C | 32°F | 273.15 K |
| Room Temperature | 25°C | 77°F | 298.15 K |
| Normal Body Temperature | 37°C | 98.6°F | 310.15 K |
| Water Boils | 100°C | 212°F | 373.15 K |
| Typical Summer in India | 40–45°C | 104–113°F | 313–318 K |
Understanding the Three Temperature Scales
- Celsius (°C): The most widely used scale globally. Water freezes at 0°C and boils at 100°C. Used in everyday weather, cooking, and medicine in India and most of the world.
- Fahrenheit (°F): Primarily used in the United States. Water freezes at 32°F and boils at 212°F. Americans describe weather, body temperature (98.6°F), and cooking in Fahrenheit.
- Kelvin (K): The SI base unit used in science and engineering. Starts at absolute zero (0 K = −273.15°C) — the coldest possible temperature. No negative values exist on the Kelvin scale. Used in physics, chemistry, and astrophysics.
Frequently Asked Questions (FAQs)
How do you convert Celsius to Fahrenheit?
Use the formula: °F = (°C × 9/5) + 32. For example, to convert 30°C: (30 × 9/5) + 32 = 54 + 32 = 86°F. A quick mental shortcut: double the Celsius value and add 30 for an approximate Fahrenheit value.
How do you convert Fahrenheit to Celsius?
Use the formula: °C = (°F − 32) × 5/9. For example, 98.6°F = (98.6 − 32) × 5/9 = 66.6 × 5/9 = 37°C — this is normal human body temperature.
What is absolute zero?
Absolute zero (0 Kelvin = −273.15°C = −459.67°F) is the lowest theoretical temperature possible. At this point, all molecular motion stops and a substance has no thermal energy. No physical object has ever been cooled completely to absolute zero, though scientists have come extremely close in laboratory conditions.
At what temperature are Celsius and Fahrenheit equal?
Celsius and Fahrenheit are equal at −40 degrees. That is, −40°C = −40°F. This is the one unique intersection point of both scales. You can verify: °F = (−40 × 9/5) + 32 = −72 + 32 = −40°F.
Why is Kelvin used in science instead of Celsius?
Kelvin starts at absolute zero with no negative temperatures, making thermodynamic and gas law calculations mathematically consistent. For example, Charles’s Law (V ∝ T) only works correctly when temperature is expressed in Kelvin, not Celsius.