Temperature Conversion Master Guide: Celsius, Fahrenheit, Kelvin & More

Temperature conversion is one of the most common unit conversions people need, whether you're cooking, traveling, studying science, or just checking the weather. Unlike simple length or weight conversions that use multiplication, temperature conversions require specific formulas because different temperature scales have different zero points and intervals.

Quick Answer: Use our unit converter for instant, accurate conversions. We support all major measurement types including length, weight, volume, temperature, and more.

This comprehensive guide covers everything you need to know about converting between Celsius, Fahrenheit, Kelvin, and other temperature scales.

Understanding Temperature Scales

Celsius (°C) - The Metric Standard

Celsius is the most widely used temperature scale globally. It's part of the metric system and is used in:

• Most countries worldwide (except the US)
• Scientific research
• Weather reporting (outside the US)
• Cooking and baking (in metric countries)

Key Reference Points:

• 0°C = Freezing point of water
• 100°C = Boiling point of water
• 20-25°C = Comfortable room temperature
• 37°C = Normal human body temperature

Use our Celsius converter to convert Celsius to any other temperature scale.

Fahrenheit (°F) - The US Standard

Fahrenheit is primarily used in the United States, though it's also used in some Caribbean countries. It has a smaller degree interval than Celsius, making it more precise for everyday weather reporting.

Key Reference Points:

• 32°F = Freezing point of water
• 212°F = Boiling point of water
• 68-77°F = Comfortable room temperature
• 98.6°F = Normal human body temperature

Convert Fahrenheit to Celsius using our Fahrenheit to Celsius converter.

Kelvin (K) - The Scientific Standard

Kelvin is the SI base unit for temperature and is used primarily in scientific contexts. It's an absolute temperature scale where 0 K (absolute zero) is the theoretical point where all molecular motion stops.

Key Facts:

• 0 K = Absolute zero (-273.15°C)
• 273.15 K = Freezing point of water (0°C)
• 373.15 K = Boiling point of water (100°C)
• No negative values (absolute zero is the minimum)

Convert Kelvin to Celsius with our Kelvin converter.

Temperature Conversion Formulas

Celsius to Fahrenheit

The most common conversion people need:

Formula: °F = (°C × 9/5) + 32

Examples:

• 0°C = (0 × 9/5) + 32 = 32°F
• 20°C = (20 × 9/5) + 32 = 68°F
• 100°C = (100 × 9/5) + 32 = 212°F
• 37°C = (37 × 9/5) + 32 = 98.6°F

Quick Approximation: Double the Celsius temperature and add 30

• 20°C ≈ (20 × 2) + 30 = 70°F (actual: 68°F)

Use our Celsius to Fahrenheit converter for accurate conversions.

Fahrenheit to Celsius

Formula: °C = (°F - 32) × 5/9

Examples:

• 32°F = (32 - 32) × 5/9 = 0°C
• 68°F = (68 - 32) × 5/9 = 20°C
• 212°F = (212 - 32) × 5/9 = 100°C
• 98.6°F = (98.6 - 32) × 5/9 = 37°C

Quick Approximation: Subtract 30 and divide by 2

• 70°F ≈ (70 - 30) ÷ 2 = 20°C (actual: 21.1°C)

Convert Fahrenheit to Celsius instantly with our Fahrenheit to Celsius converter.

Celsius to Kelvin

This is the simplest conversion because Kelvin uses the same degree interval as Celsius:

Formula: K = °C + 273.15

Examples:

• 0°C = 0 + 273.15 = 273.15 K
• 20°C = 20 + 273.15 = 293.15 K
• 100°C = 100 + 273.15 = 373.15 K
• -273.15°C = 0 K (absolute zero)

Use our temperature converter to convert to Kelvin.

Fahrenheit to Kelvin

Formula: K = (°F - 32) × 5/9 + 273.15

Or convert via Celsius: First convert °F to °C, then add 273.15

Examples:

• 32°F = 273.15 K (freezing point)
• 212°F = 373.15 K (boiling point)
• 98.6°F = 310.15 K (body temperature)

Temperature Conversion Table

Here's a quick reference table for common temperatures:

Celsius	Fahrenheit	Kelvin	Description
-40°C	-40°F	233.15 K	The point where Celsius and Fahrenheit are equal
0°C	32°F	273.15 K	Freezing point of water
10°C	50°F	283.15 K	Cool day
20°C	68°F	293.15 K	Room temperature
25°C	77°F	298.15 K	Warm room temperature
37°C	98.6°F	310.15 K	Normal body temperature
100°C	212°F	373.15 K	Boiling point of water
175°C	347°F	448.15 K	Moderate oven
200°C	392°F	473.15 K	Hot oven
230°C	446°F	503.15 K	Very hot oven

Cooking Temperature Conversions

Cooking is one of the most practical applications of temperature conversion. Here are common cooking temperatures:

Oven Temperatures

Description	Celsius	Fahrenheit
Very low	120°C	250°F
Low	150°C	300°F
Moderate	180°C	350°F
Hot	200°C	400°F
Very hot	230°C	450°F
Extremely hot	260°C	500°F

Convert any cooking temperature using our temperature converter.

Meat Cooking Temperatures

Beef (Medium Rare): 54-57°C (130-135°F) Beef (Medium): 60-63°C (140-145°F) Beef (Well Done): 71°C+ (160°F+) Pork: 63°C (145°F) Chicken: 74°C (165°F) Fish: 63°C (145°F)

Baking Temperature Guide

Bread: 190-220°C (375-425°F) Cakes: 175-190°C (350-375°F) Cookies: 175-190°C (350-375°F) Pies: 200-220°C (400-425°F)

Scientific Temperature Conversions

Kelvin in Physics and Chemistry

Kelvin is essential in scientific calculations because:

1. It's an absolute scale (no negative values)
2. It's directly proportional to kinetic energy
3. Many physical laws use Kelvin (e.g., ideal gas law)

Common Scientific Conversions:

• Room temperature: 293.15 K (20°C)
• Standard temperature: 273.15 K (0°C)
• Absolute zero: 0 K (-273.15°C)

Convert to Kelvin using our temperature converter.

Other Temperature Scales

While less common, there are other historical temperature scales:

Rankine (°R): Used in some engineering applications

• 0°R = Absolute zero
• °R = °F + 459.67

Réaumur (°Ré): Historical scale, rarely used today

• 0°Ré = Freezing point of water
• 80°Ré = Boiling point of water

Rømer (°Rø): Historical Danish scale

• 0°Rø = Freezing point of brine
• 60°Rø = Boiling point of water

Practical Conversion Tips

Mental Math Shortcuts

Celsius to Fahrenheit (Approximate):

1. Double the Celsius temperature
2. Add 30
3. Result is close to Fahrenheit

Example: 20°C → (20 × 2) + 30 = 70°F (actual: 68°F)

Fahrenheit to Celsius (Approximate):

1. Subtract 30 from Fahrenheit
2. Divide by 2
3. Result is close to Celsius

Example: 70°F → (70 - 30) ÷ 2 = 20°C (actual: 21.1°C)

Note: These approximations are within 2-3 degrees for typical temperatures (0-100°C).

Quick Reference Points

Memorize these key temperatures for quick reference:

• -40°C = -40°F (the crossover point)
• 0°C = 32°F (freezing)
• 20°C = 68°F (room temp)
• 37°C = 98.6°F (body temp)
• 100°C = 212°F (boiling)

Weather Temperature Ranges

Understanding temperature ranges helps with weather interpretation:

Description	Celsius Range	Fahrenheit Range
Extremely cold	Below -18°C	Below 0°F
Very cold	-18°C to -7°C	0°F to 20°F
Cold	-7°C to 4°C	20°F to 40°F
Cool	4°C to 13°C	40°F to 55°F
Mild	13°C to 18°C	55°F to 65°F
Warm	18°C to 24°C	65°F to 75°F
Hot	24°C to 32°C	75°F to 90°F
Very hot	Above 32°C	Above 90°F

Common Temperature Conversion Mistakes

Mistake 1: Simple Addition/Subtraction

Wrong: 20°C + 32 = 52°F Correct: (20°C × 9/5) + 32 = 68°F

Temperature conversion requires both multiplication and addition, not just addition.

Mistake 2: Forgetting the Order of Operations

Wrong: °F = °C × 9/5 + 32 (if calculated as °C × 9 ÷ 5 + 32 incorrectly) Correct: °F = (°C × 9/5) + 32

Always multiply first, then add.

Mistake 3: Confusing Celsius and Fahrenheit Recipes

When following international recipes, always check which scale is used. European recipes use Celsius, while American recipes use Fahrenheit.

Use our temperature converter to avoid mistakes.

Temperature Conversion Tools

For accurate conversions, use our comprehensive temperature converter which supports:

• Celsius to Fahrenheit and vice versa
• Celsius to Kelvin and vice versa
• Fahrenheit to Kelvin and vice versa
• All other temperature scales

Our converter handles all the complex formulas automatically, ensuring accuracy for cooking, scientific work, and everyday use.

Frequently Asked Questions

What is the difference between metric and imperial systems?

The metric system uses base-10 units (meters, kilograms, liters) and is used worldwide. The imperial system uses inches, pounds, and gallons, primarily used in the United States. Metric is easier to convert because everything is in multiples of 10.

How do I convert units quickly in my head?

Use approximations: for km to miles multiply by 0.6, for kg to lbs multiply by 2, for Celsius to Fahrenheit double and add 30. These give rough estimates that are usually close enough for everyday use.

Why do different countries use different measurement systems?

Historical reasons. The US adopted the British Imperial system before the metric system was widely adopted. Most countries switched to metric in the 20th century for international trade and scientific consistency.

Related Articles

You might also find these guides helpful:

• Metric vs Imperial: Complete Comparison Guide for 2025: Understand the differences between metric and imperial systems. Learn when to use each, conversion formulas, and practical examples for length, weight, volume, and temperature.

• Speed and Velocity Conversions: Complete Guide to MPH, KM/H, M/S & More: Master speed conversions between miles per hour, kilometers per hour, meters per second, knots, and Mach. Essential for driving, aviation, and physics.

• Time Conversion Complete Guide: Seconds, Minutes, Hours, Days & More: Master time conversions between seconds, minutes, hours, days, weeks, months, and years. Essential for scheduling, calculations, and understanding time measurements.

Your Next Steps

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Conclusion

Key Takeaways:

• ✅ Use our converter tools for accuracy
• ✅ Bookmark converters for quick access
• ✅ Double-check critical conversions
• ✅ Learn common mental math shortcuts
• ✅ Explore related guides for more tips

Temperature conversion is essential for cooking, travel, science, and everyday life. While the formulas may seem complex at first, with practice and the use of conversion tools, you'll master temperature conversions quickly.

Remember:

• Celsius to Fahrenheit: Multiply by 9/5, then add 32
• Fahrenheit to Celsius: Subtract 32, then multiply by 5/9
• Celsius to Kelvin: Simply add 273.15
• For cooking: Use our temperature converter to ensure perfect results

For quick, accurate temperature conversions anytime, use our temperature converter which supports all major temperature scales and provides instant, precise results.