Temperature Converter
Convert temperatures between Celsius, Fahrenheit, and Kelvin instantly with our free online converter.
Temperature Scale Fundamentals
Temperature exists on three main scales used around the world. Whether you're cooking with a recipe from another country, checking weather reports internationally, or working in science, you'll need to convert between these scales. Our converter makes it instant and accurate.
Temperature Converter
Quick Reference Temperatures
Conversion Formulas
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 Provides:
- ✓Instant conversion between all three temperature scales
- ✓Accurate to 2 decimal places for precise calculations
- ✓Common temperature references for quick lookups
- ✓Visible formulas to understand the math
Temperature Conversion: Celsius, Fahrenheit, and Kelvin Explained
Temperature exists on three main scales, and switching between them can be confusing if you don't know the formulas. Fahrenheit is mostly used in the United States. Celsius is the standard everywhere else on Earth. Kelvin is what scientists use. The good news? Once you understand the relationship between them, conversion becomes straightforward. Whether you're cooking with a European recipe, reading weather in another country, or just curious about how these systems work, this guide walks you through it all.
The Three Temperature Scales at a Glance
Celsius (°C)
- Freezing: 0°C
- Boiling: 100°C
- Room temp: ~20°C
- Standard for most countries
Fahrenheit (°F)
- Freezing: 32°F
- Boiling: 212°F
- Room temp: ~68°F
- Used in USA
Kelvin (K)
- Freezing: 273.15K
- Boiling: 373.15K
- Absolute zero: 0K
- Scientific standard
Real-World Conversion Examples
Cooking Scenario: European Recipe
Recipe calls for 180°C. What's that in Fahrenheit?
Formula: (°C × 9/5) + 32 = °F
Calculation: (180 × 9/5) + 32 = 324 + 32 = 356°F
Result: Set your oven to 350-360°F
Weather Scenario: US Temperature to Celsius
Weather report says 68°F. How warm is that in Celsius?
Formula: (°F - 32) × 5/9 = °C
Calculation: (68 - 32) × 5/9 = 36 × 5/9 = 20°C
Result: Pleasant room temperature
Quick Reference: Common Temperature Conversions
| Celsius | Fahrenheit | What It Feels Like |
|---|---|---|
| -18°C | 0°F | Very cold, snow likely |
| 0°C | 32°F | Freezing point |
| 10°C | 50°F | Cool, light jacket |
| 20°C | 68°F | Comfortable room temperature |
| 25°C | 77°F | Warm, pleasant day |
| 30°C | 86°F | Hot, consider air conditioning |
| 37°C | 98.6°F | Normal body temperature |
| 40°C | 104°F | Very hot, danger zone |
| 100°C | 212°F | Boiling point of water |
Why These Three Scales Exist
Celsius: Science-Friendly
Based on water's freezing (0°) and boiling (100°) points. Makes it intuitive for scientists and creates a 100-degree range that's easy to work with.
Fahrenheit: Historical Quirk
Daniel Fahrenheit wanted his thermometer divisions to not require decimals for common temperatures. Weird origin story, but the US stuck with it.
Kelvin: Absolute Science
Starts at absolute zero (coldest possible temperature). Used in physics, chemistry, and anywhere precision matters for calculations.
Common Temperature Conversion Questions
Why doesn't the US use Celsius like everyone else?
Historical reasons, mainly. The US adopted Fahrenheit first, and switching entire systems is enormously complicated and expensive. A few other countries use Fahrenheit too (Bahamas, Belize, etc.).
When do I use Kelvin?
Mostly in scientific calculations where you need absolute values. Weather, cooking, and everyday conversations stick to Celsius or Fahrenheit. You won't encounter Kelvin unless you're studying science.
Is there a simple way to remember conversions?
For rough estimates: Add 30 to Celsius and multiply by 2 for a quick (but imperfect) Fahrenheit estimate. Or subtract 30 and divide by 2 for the reverse. Our converter is more accurate though!
What temperature do I cook chicken to?
165°F or 74°C minimum internal temperature. Use a meat thermometer to check—it's the safest way to know when poultry is fully cooked.
Frequently Asked Questions
Why does the US use Fahrenheit?▼
The USA adopted the Fahrenheit scale in the 1700s. Despite its historical origin, changing nationwide systems would be impractical and expensive. However, the US scientific community uses Celsius for research and calculations.
What is absolute zero?▼
Absolute zero is the lowest possible temperature in the universe. It equals 0 Kelvin, -273.15°C, or -459.67°F. At absolute zero, all molecular motion stops. It's a theoretical limit that cannot actually be achieved.
When should I use Kelvin?▼
Kelvin is primarily used in scientific and engineering contexts where absolute temperature matters. Daily life uses Celsius or Fahrenheit. If you're cooking, checking weather, or doing non-scientific work, stick with Celsius or Fahrenheit.