Temperature Conversion Formulas
Complete guide to temperature conversion formulas between Celsius, Fahrenheit, Kelvin, and Rankine
Try It Yourself
People also convert:
Keyboard Shortcuts:
🌡️ Celsius to Fahrenheit
Formula
°F = (°C × 9/5) + 32
or equivalently:
°F = (°C × 1.8) + 32
Step-by-Step Instructions
- Take your temperature in Celsius
- Multiply it by 9/5 (which equals 1.8)
- Add 32 to the result
- The answer is your temperature in Fahrenheit
Example Calculation
Convert 25°C to Fahrenheit:
Step 1: 25 × 9/5 = 25 × 1.8 = 45
Step 2: 45 + 32 = 77
Answer: 25°C = 77°F
🌡️ Fahrenheit to Celsius
Formula
°C = (°F - 32) × 5/9
or equivalently:
°C = (°F - 32) ÷ 1.8
Step-by-Step Instructions
- Take your temperature in Fahrenheit
- Subtract 32 from it
- Multiply the result by 5/9 (or divide by 1.8)
- The answer is your temperature in Celsius
Example Calculation
Convert 68°F to Celsius:
Step 1: 68 - 32 = 36
Step 2: 36 × 5/9 = 36 ÷ 1.8 = 20
Answer: 68°F = 20°C
🔬 Celsius to Kelvin
Formula
K = °C + 273.15
Step-by-Step Instructions
- Take your temperature in Celsius
- Add 273.15 to it
- The answer is your temperature in Kelvin
Example Calculation
Convert 20°C to Kelvin:
20 + 273.15 = 293.15
Answer: 20°C = 293.15 K
🔬 Kelvin to Celsius
Formula
°C = K - 273.15
Step-by-Step Instructions
- Take your temperature in Kelvin
- Subtract 273.15 from it
- The answer is your temperature in Celsius
Example Calculation
Convert 300 K to Celsius:
300 - 273.15 = 26.85
Answer: 300 K = 26.85°C
🌡️🔬 Fahrenheit to Kelvin
Formula
K = (°F - 32) × 5/9 + 273.15
Step-by-Step Instructions
- Take your temperature in Fahrenheit
- Subtract 32 from it
- Multiply the result by 5/9
- Add 273.15 to the result
- The answer is your temperature in Kelvin
Example Calculation
Convert 77°F to Kelvin:
Step 1: 77 - 32 = 45
Step 2: 45 × 5/9 = 25
Step 3: 25 + 273.15 = 298.15
Answer: 77°F = 298.15 K
🔬🌡️ Kelvin to Fahrenheit
Formula
°F = (K - 273.15) × 9/5 + 32
Step-by-Step Instructions
- Take your temperature in Kelvin
- Subtract 273.15 from it
- Multiply the result by 9/5
- Add 32 to the result
- The answer is your temperature in Fahrenheit
Example Calculation
Convert 298.15 K to Fahrenheit:
Step 1: 298.15 - 273.15 = 25
Step 2: 25 × 9/5 = 45
Step 3: 45 + 32 = 77
Answer: 298.15 K = 77°F
⚙️ Rankine Conversions
Celsius to Rankine
°R = (°C + 273.15) × 9/5
Example: 20°C = 527.67°R
Rankine to Celsius
°C = (°R × 5/9) - 273.15
Example: 527.67°R = 20°C
Fahrenheit to Rankine
°R = °F + 459.67
Example: 68°F = 527.67°R
Rankine to Fahrenheit
°F = °R - 459.67
Example: 527.67°R = 68°F
📋 All Formulas Quick Reference
| From | To | Formula |
|---|---|---|
| Celsius | Fahrenheit | °F = (°C × 9/5) + 32 |
| Fahrenheit | Celsius | °C = (°F - 32) × 5/9 |
| Celsius | Kelvin | K = °C + 273.15 |
| Kelvin | Celsius | °C = K - 273.15 |
| Fahrenheit | Kelvin | K = (°F - 32) × 5/9 + 273.15 |
| Kelvin | Fahrenheit | °F = (K - 273.15) × 9/5 + 32 |
| Celsius | Rankine | °R = (°C + 273.15) × 9/5 |
| Rankine | Celsius | °C = (°R × 5/9) - 273.15 |
| Fahrenheit | Rankine | °R = °F + 459.67 |
| Rankine | Fahrenheit | °F = °R - 459.67 |
🧮 Understanding Temperature Scales
Celsius (°C)
- Water freezes at 0°C
- Water boils at 100°C
- Used by most of the world
- Also called Centigrade
Fahrenheit (°F)
- Water freezes at 32°F
- Water boils at 212°F
- Used primarily in the USA
- Finer gradations than Celsius
Kelvin (K)
- Absolute zero at 0 K
- Water freezes at 273.15 K
- Used in scientific contexts
- No negative temperatures
Rankine (°R)
- Absolute zero at 0°R
- Water freezes at 491.67°R
- Used in engineering (USA)
- Fahrenheit-based absolute scale
💡 Tips and Tricks
Quick Mental Math for C to F:
Double the Celsius, subtract 10%, then add 32. Example: 20°C → 40 - 4 + 32 = 68°F (exact!)
The -40 Rule:
-40°C = -40°F. This is the only temperature where both scales meet!
Why 32 and 273.15?:
These are the freezing points of water in Fahrenheit and Kelvin. The formulas shift between these reference points.
Room Temperature:
20°C = 68°F = 293.15 K = 527.67°R. Memorize this for quick comparisons!
More Temperature Resources
You might also likeStatCalcProfor statistics homework helpers.