Temperature Converter

Convert Celsius, Fahrenheit, and Kelvin instantly

💡 Tip: Press Ctrl+D for dark mode, Ctrl+K to focus converter

🌡️ Temperature Converter

Convert between Celsius, Fahrenheit, and Kelvin

💡 Quick Formula: °F = (°C × 9/5) + 32
25°C = 77°F

Temperature Conversion Guide

Common Temperature Conversions

Celsius (°C) Fahrenheit (°F) Kelvin (K) Description
-273.15 -459.67 0 Absolute Zero
-40 -40 233.15 C and F are equal
-18 0 255.15 Freezer temperature
0 32 273.15 Water freezes
10 50 283.15 Cool day
20 68 293.15 Room temperature
25 77 298.15 Warm room
37 98.6 310.15 Human body temp
100 212 373.15 Water boils

Understanding Temperature Scales

Celsius (°C) - Centigrade

Creator: Anders Celsius (1742)

Used in: Most of the world, scientific community

Definition: 0°C is the freezing point of water, 100°C is the boiling point (at sea level)

Named after: Swedish astronomer Anders Celsius

Fun fact: Originally, Celsius defined 0° as boiling and 100° as freezing - it was later reversed!

Fahrenheit (°F)

Creator: Daniel Gabriel Fahrenheit (1724)

Used in: United States, Cayman Islands, Bahamas, Liberia

Definition: 32°F is the freezing point of water, 212°F is the boiling point (at sea level)

Named after: German physicist Daniel Gabriel Fahrenheit

Fun fact: Fahrenheit chose 0° as the coldest temperature he could create with ice, water, and salt!

Kelvin (K)

Creator: William Thomson, Lord Kelvin (1848)

Used in: Scientific research, astronomy, physics

Definition: 0 K is absolute zero (the coldest possible temperature), 273.15 K is water's freezing point

Named after: British physicist Lord Kelvin

Fun fact: Kelvin has no negative values - nothing can be colder than 0 K! Also, we say "kelvin" not "degrees kelvin"

Conversion Formulas

Celsius to Fahrenheit:

°F = (°C × 9/5) + 32
or
°F = (°C × 1.8) + 32

Fahrenheit to Celsius:

°C = (°F - 32) × 5/9
or
°C = (°F - 32) ÷ 1.8

Celsius to Kelvin:

K = °C + 273.15

Kelvin to Celsius:

°C = K - 273.15

Fahrenheit to Kelvin:

K = (°F - 32) × 5/9 + 273.15

Kelvin to Fahrenheit:

°F = (K - 273.15) × 9/5 + 32

Practical Examples

  • ☀️ Hot Summer Day: 35°C = 95°F = 308.15 K
  • ❄️ Cold Winter Day: -10°C = 14°F = 263.15 K
  • 🍕 Pizza Oven: 260°C = 500°F = 533.15 K
  • 🧊 Dry Ice: -78.5°C = -109.3°F = 194.65 K
  • 🌡️ Fever: 38°C = 100.4°F = 311.15 K
  • 🔥 Candle Flame: ~1000°C = ~1832°F = ~1273 K
  • ☕ Hot Coffee: 60°C = 140°F = 333.15 K
  • 🌊 Ocean Surface: ~17°C = ~63°F = ~290 K

Why Different Temperature Scales?

Each temperature scale was developed for different purposes:

  • 🌍 Celsius: Based on water's freezing/boiling points - practical for everyday use and weather
  • 🇺🇸 Fahrenheit: More granular for weather (0-100°F covers most habitable temperatures)
  • 🔬 Kelvin: No negative values - perfect for scientific calculations and physics

Quick Mental Math Tricks

Celsius to Fahrenheit (approximate):

  • Double the °C, then add 30 → Example: 20°C → (20 × 2) + 30 = 70°F (actual: 68°F) ✓
  • More accurate: Double the °C, subtract 10%, then add 32

Fahrenheit to Celsius (approximate):

  • Subtract 30, then divide by 2 → Example: 70°F → (70 - 30) ÷ 2 = 20°C (actual: 21°C) ✓
  • More accurate: Subtract 32, then divide by 1.8

Celsius to Kelvin:

  • Just add 273 (for rough estimates) → Example: 25°C + 273 ≈ 298 K
  • Exact: Add 273.15

Frequently Asked Questions

How do I convert Celsius to Fahrenheit?

Multiply the Celsius temperature by 1.8 (or 9/5), then add 32. Formula: °F = (°C × 1.8) + 32. For example, 25°C = (25 × 1.8) + 32 = 77°F.

How do I convert Fahrenheit to Celsius?

Subtract 32 from the Fahrenheit temperature, then multiply by 5/9 (or divide by 1.8). Formula: °C = (°F - 32) × 5/9. For example, 77°F = (77 - 32) × 5/9 = 25°C.

At what temperature are Celsius and Fahrenheit equal?

At -40 degrees. Both -40°C and -40°F represent exactly the same temperature. This is the only point where the two scales intersect.

What is absolute zero?

Absolute zero is the coldest possible temperature, where all molecular motion stops. It equals -273.15°C, -459.67°F, or 0 K (Kelvin). Nothing in the universe can be colder than absolute zero.

Why doesn't the US use Celsius?

The US uses Fahrenheit due to historical reasons. When the metric system was developed, the US had already established Fahrenheit for weather, cooking, and daily life. While scientists use Celsius/Kelvin, switching the entire country would be extremely costly and disruptive.

Why is Kelvin used in science?

Kelvin has no negative values (starts at absolute zero) and uses the same degree size as Celsius. This makes mathematical calculations simpler in physics, chemistry, and engineering, especially when dealing with gas laws and thermodynamics.

Is 0°F colder than 0°C?

Yes! 0°F = -17.78°C. Fahrenheit's 0° was originally set as the coldest temperature Fahrenheit could create with a mixture of ice, water, and salt.

Quick Reference Chart

Common Weather Temperatures:

  • -18°C = 0°F (Very cold winter day)
  • 0°C = 32°F (Freezing point)
  • 10°C = 50°F (Cool day)
  • 20°C = 68°F (Comfortable room)
  • 30°C = 86°F (Hot summer day)
  • 37°C = 98.6°F (Body temperature)
  • 40°C = 104°F (Extreme heat)

Cooking Temperatures:

  • 120°C = 250°F (Low oven)
  • 160°C = 320°F (Moderate oven)
  • 180°C = 350°F (Common baking temp)
  • 200°C = 400°F (High heat)
  • 230°C = 450°F (Very high heat)