Temperature Converter: How to Convert Between Celsius, Fahrenheit, and Kelvin Like a Pro

Whether you’re baking a cake, checking the weather abroad, or running a science experiment, knowing how to convert temperatures between Celsius, Fahrenheit, and Kelvin is a practical skill that comes up more often than you think. Here’s how to master it — and when to use each scale.

When to Use Each Temperature Scale

Celsius (°C) is the standard in most countries for weather, cooking, and daily life. Water freezes at 0°C and boils at 100°C, making it intuitive for everyday use.

Fahrenheit (°F) is primarily used in the United States. It’s common in American recipes, oven settings, and weather forecasts. Oven temperatures are typically given in Fahrenheit in US cookbooks, so if you’re following an American recipe abroad, conversion is essential.

Kelvin (K) is the scientific standard. It starts at absolute zero (−273.15°C), the point where all molecular motion stops. You’ll encounter Kelvin in physics, chemistry, astronomy, and engineering — anywhere precise thermal measurements matter.

Quick Reference: Common Temperatures You Need to Know

Memorize these key reference points to make quick mental conversions:

Freezing point of water: 0°C = 32°F = 273.15 K
Room temperature: 20°C = 68°F (comfortable indoor temp)
Human body temperature: 37°C = 98.6°F
Hot bath: 40°C = 104°F
Boiling point of water: 100°C = 212°F = 373.15 K
Common oven temperature (350°F): 177°C — the standard for baking cakes and cookies
Absolute zero: −273.15°C = −459.67°F = 0 K

Real-World Temperature Conversion Examples

Cooking and Baking

American recipes often call for oven temperatures in Fahrenheit. If a recipe says preheat to 375°F and your oven uses Celsius, you need 190°C. For European recipes in Celsius? 200°C translates to about 400°F — perfect for roasting vegetables.

Weather and Travel

Traveling from the US to Europe? A forecast of 30°C sounds hot — and it is — that’s 86°F. Meanwhile, 0°C (32°F) means freezing conditions. A quick rule of thumb: subtract 30 from Fahrenheit and halve the result for a rough Celsius estimate. For example, 90°F → (90 − 30) ÷ 2 = 30°C. Close enough!

Science and Lab Work

In a lab, you almost always work in Kelvin. If an experiment requires 300 K, that’s 26.85°C — roughly room temperature. Room temperature in Kelvin is about 293 K (20°C).

How to Use Our Online Temperature Converter

The easiest way to get accurate conversions without memorizing formulas is to use the Today Calculator Temperature Converter. Simply select your starting scale, enter the value, choose the target scale, and get an instant result. It handles all six conversion directions between Celsius, Fahrenheit, and Kelvin with precision.

For quick mental math, remember these formulas:

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

Whether you’re cooking a perfect roast, packing for a trip, or acing a science project, knowing these conversions — and having a reliable converter at hand — makes temperature work effortless.