Temperature conversion is the process of converting a temperature value from one scale to another using standard mathematical formulas. Temperature is measured using three primary scales: Celsius (°C), Fahrenheit (°F), and Kelvin (K).
Each scale has fixed reference points based on the physical properties of water, which makes comparison and conversion between the scales easier and more accurate.
The formulas below help convert temperature values between these scales.
These formulas allow accurate and easy conversion between Celsius, Fahrenheit, and Kelvin.
Units of Temperature
Temperature is measured in three units: Celsius (°C), Fahrenheit (°F), and Kelvin (K).
Kelvin is the SI unit used in science, while Celsius and Fahrenheit are commonly used in daily life.
Celsius (°C)
The Celsius scale was introduced in 1742 by Swedish astronomer Anders Celsius. It is based on the freezing point of water at 0°C and the boiling point at 100°C. The normal human body temperature is 37°C.
Fahrenheit (°F)
The Fahrenheit scale was developed by Daniel Gabriel Fahrenheit. In this scale, water freezes at 32°F and boils at 212°F. The normal human body temperature is 98.6°F.
Kelvin (K)
Kelvin is the SI unit of temperature, named after William Thomson (Lord Kelvin). Water freezes at 273.15 K and boils at 373.15 K. The degree symbol (°) is not used in Kelvin.
Temperature Conversion Formula Between Celsius and Kelvin
Where,
- T(°C) = Temperature in Celsius
- T (K) = Temperature in Kelvin
Temperature Conversion Formulas Between Fahrenheit and Celsius
Where,
- C = Measure of temperature in degrees Celsius (°C).
- F = Measure of temperature in degrees Fahrenheit (°F).
Temperature Conversion Formulas Between Fahrenheit and Kelvin
Where,
K = Measure of temperature in Kelvin (K).
F = Measure of temperature in degrees Fahrenheit (°F).
Temperature Conversion Chart
The table below shows equivalent temperature values in Celsius, Fahrenheit, and Kelvin, including important reference points such as the freezing point of water, normal body temperature, and the boiling point of water.
| Kelvin (K) | Celsius (°C) | Fahrenheit (°F) |
|---|---|---|
| 273.15 K | 0°C (Freezing point of water) | 32°F |
| 274.15 K | 1°C | 33.8°F |
| 275.15 K | 2°C | 35.6°F |
| 276.15 K | 3°C | 37.4°F |
| 277.15 K | 4°C | 39.2°F |
| 278.15 K | 5°C | 41.0°F |
| 283.15 K | 10°C | 50.0°F |
| 288.15 K | 15°C | 59.0°F |
| 293.15 K | 20°C | 68.0°F |
| 298.15 K | 25°C | 77.0°F |
| 303.15 K | 30°C | 86.0°F |
| 308.15 K | 35°C | 95.0°F |
| 310.15 K | 37°C (Normal body temperature) | 98.6°F |
| 313.15 K | 40°C | 104.0°F |
| 323.15 K | 50°C | 122.0°F |
| 333.15 K | 60°C | 140.0°F |
| 343.15 K | 70°C | 158.0°F |
| 353.15 K | 80°C | 176.0°F |
| 363.15 K | 90°C | 194.0°F |
| 373.15 K | 100°C (Boiling point of water) | 212.0°F |
| 473.15 K | 200°C | 392.0°F |
Sample Problems
Question 1: Convert the temperature 20°C to Fahrenheit using the Temperature conversion formula.
Solution:
Given, Celsius (C) = 20°C
Fahrenheit (F) = C × (9/5) + 32
= 20 × (9/5) + 32
= 36 + 32
= 68°F
Therefore 20°C = 68°F
Question 2: Convert the temperature 50°F to Celsius using the Temperature conversion formula.
Solution:
Given, Fahrenheit (F) = 50°F
Celsius (C) = (F - 32) × (5/9)
= (50 - 32) × (5/9)
= 18 × (5/9)
=10°C
Therefore 50°F = 10°C
Question 3: Convert the temperature to 32°C to Kelvin using the Temperature conversion formula.
Solution:
Given, Celsius (C) = 32°C
Kelvin (K) = C + 273.15
= 32 + 273.15
= 305.15K
Therefore 32°C = 305.15K
Question 4: Convert the temperature 275K to °C using the Temperature conversion formula.
Solution:
Given, Kelvin (K) = 275K
Celsius (C) = K - 273.15
= 275 - 273.15
= 1.85°C
Therefore 275K = 1.85°C
Question 5: Convert the temperature 59°F to Kelvin using the Temperature conversion formula.
Solution:
Given, Fahrenheit (F) = 59°F
Kelvin (K) = (F - 32) × (5/9) + 273.15
= (59 - 32) × (5/9) + 273.15
= 27 × (5/9) + 273.15
= 3 × (5) + 273.15
= 15 + 273.15
= 288.15K
Therefore 59°F = 288.15K
Question 6: Convert the temperature 300K to Fahrenheit using the Temperature conversion formula.
Solution:
Given, Kelvin (K) = 300K
Fahrenheit (F) = (K - 273.15) × (9/5) + 32
= (300 - 273.15) × (9/5) + 32
= 26.85 × (9/5) + 32
= 48.33 + 32
= 80.33°F
Therefore 300K = 80.33°F
Practice Problem Based on Temperature Conversion Formulas
Question 1. First, convert -40°F to Kelvin, and then to Celsius. In Celsius, what is the final temperature?
Question 2. In a laboratory experiment, a scientist records a temperature of 150°C. Convert this temperature to Kelvin and Fahrenheit. Next, figure out how much the Celsius and Kelvin values differ from one another.
Question 3. Water has a boiling point of 212°F. Determine the difference between the two converted temperatures by converting this one to both Celsius and Kelvin.
Question 4. A desert location records a temperature of 100°F. After that, the temperature is raised by 30°C. Determine the difference between the two Kelvin values after converting the temperatures (before and after the increase) to Kelvin.
Answer:-
- 233.15 K, -40°C
- 423.15 K, 302°F
- Difference between Celsius and Kelvin: 273.15 K, 100°C, 373.15 K
- 310.93 K, 303.15 K, 7.78 K