Temperature Converter – Celsius, Fahrenheit & Kelvin

Temperature Converter: Convert Celsius, Fahrenheit, Kelvin, and Rankine

Temperature is one of the few measurements where you can't just multiply by a fixed number to convert it. Checking a weather forecast from another country, following an oven temperature in a foreign recipe, or working through a physics problem all require converting between different temperature scales correctly. A temperature converter handles the formula for you, so there's no risk of a calculation mistake.

Why Temperature Conversion Isn't a Simple Ratio

Length or weight conversion is just multiplication (1 foot × 0.3048 = meters), because both units start counting from the same zero point. Temperature scales don't share a common zero. Celsius sets 0° at the freezing point of water, Fahrenheit sets 32° at the same point, and Kelvin starts at absolute zero. Because of this offset, converting between them requires a formula rather than a ratio:

• Celsius to Fahrenheit: °F = (°C × 9/5) + 32
• Fahrenheit to Celsius: °C = (°F − 32) × 5/9
• Celsius to Kelvin: K = °C + 273.15
• Kelvin to Celsius: °C = K − 273.15

This converter also supports Rankine, an absolute temperature scale used occasionally in engineering, calculated as °R = (°C + 273.15) × 9/5.

Common Temperature Conversions

These are calculated using the exact formulas above, not rounded approximations:

• 0°C = 32°F (freezing point of water)
• 100°C = 212°F (boiling point of water at sea level)
• 20°C = 68°F (typical room temperature)
• 37°C ≈ 98.6°F (average human body temperature)
• −40°C = −40°F (the one point where both scales match)

Converting Oven Temperatures

Recipes from different countries often list oven temperatures in different scales. A common example: 180°C, a standard baking temperature in many recipes, converts to 356°F. Since most home ovens don't have fine-grained dial increments, it's common to round this to the nearest 5 or 10 degrees (350°F) — but for baking that's sensitive to temperature, using the precise converted value can make a difference.

Limitations to Keep in Mind

• Conversions use the standard mathematical formulas for each scale, so results are exact rather than approximated — any rounding you see is only for display purposes.
• Kelvin and Rankine are absolute scales, meaning negative values don't represent real physical temperatures (0 K is absolute zero). If you enter a negative Kelvin value, the converted result won't correspond to anything physically meaningful.
• Calculations happen directly in your browser using JavaScript, so there's no need to send your values to a server to get a result.

Related Conversions You Might Need

• Use the Unit Converter if you need temperature, length, weight, and other categories in one place.
• Use the Speed Converter for mph, km/h, and other speed conversions.
• Use the Weight Converter for kilograms, pounds, and ounces.
• Use the Volume Converter for liters, gallons, and cooking measurements.

Frequently Asked Questions

What temperature is 180°C in Fahrenheit for baking?

180°C converts to exactly 356°F. Many recipes round this to 350°F or 375°F depending on the oven's dial increments, but the precise value can matter for baking that's sensitive to temperature.

Why do Celsius and Fahrenheit meet at −40 degrees?

At −40, both scales produce the same number because of how their formulas relate. Solving °F = (°C × 9/5) + 32 for the point where °C = °F gives exactly −40 for both.

What is Rankine used for?

Rankine is an absolute temperature scale that uses Fahrenheit-sized degrees, starting at absolute zero. It's mostly used in specific engineering and thermodynamics contexts in the United States, rather than everyday use.

Can Kelvin or Rankine be negative?

No, not in a physically meaningful sense. Both are absolute scales starting at 0 (absolute zero), so a converted negative value in Kelvin or Rankine doesn't correspond to a real temperature.

Is normal body temperature exactly 98.6°F?

98.6°F (37°C) is the commonly cited average, but normal body temperature varies by person, time of day, and measurement method, typically within a range rather than a single fixed number.