The temperature 21°C converted to kelvin is 294.15 K.
To convert Celsius (°C) to kelvin (K), you add 273.15 to the Celsius temperature. This is because kelvin scale start at absolute zero, which is -273.15°C, so adding shifts the scale accordingly.
Conversion Tool
Result in kelvin:
Conversion Formula
The formula to convert Celsius to kelvin is:
K = °C + 273.15
This works because the kelvin temperature scale starts at absolute zero, which is -273.15°C. By adding 273.15, you shift the Celsius scale so that 0 K corresponds to absolute zero.
Example calculation for 21°C:
- Start with 21°C
- Add 273.15 to 21: 21 + 273.15 = 294.15
- The result is 294.15 K
Conversion Example
- Convert 0°C to kelvin:
- Start with 0°C
- Add 273.15: 0 + 273.15 = 273.15 K
- Result is 273.15 K
- Convert -10°C to kelvin:
- Start with -10°C
- Add 273.15: -10 + 273.15 = 263.15 K
- Result is 263.15 K
- Convert 37°C to kelvin:
- Start with 37°C
- Add 273.15: 37 + 273.15 = 310.15 K
- Result is 310.15 K
- Convert 100°C to kelvin:
- Start with 100°C
- Add 273.15: 100 + 273.15 = 373.15 K
- Result is 373.15 K
Conversion Chart
Below is a chart showing Celsius temperatures from -4.0°C to 46.0°C converted into kelvin. To read the chart, find the Celsius value in the left column, then move right to see the equivalent kelvin value. This helps quickly find conversions without calculation.
| Celsius (°C) | Kelvin (K) |
|---|---|
| -4.0 | 269.15 |
| 0.0 | 273.15 |
| 5.0 | 278.15 |
| 10.0 | 283.15 |
| 15.0 | 288.15 |
| 20.0 | 293.15 |
| 21.0 | 294.15 |
| 25.0 | 298.15 |
| 30.0 | 303.15 |
| 35.0 | 308.15 |
| 40.0 | 313.15 |
| 45.0 | 318.15 |
| 46.0 | 319.15 |
Related Conversion Questions
- What is 21 degrees Celsius in kelvin units?
- How to convert 21°C temperature to kelvin correctly?
- Is 21 Celsius higher or lower than 294 kelvin?
- What does 21°C equal in kelvin scale?
- How many kelvin correspond to 21 degrees Celsius?
- Can you show the math for converting 21 Celsius to kelvin?
- Does 21°C equal 294.15 K or a different value?
Conversion Definitions
Celsius (°C): Celsius is a temperature scale where 0 degrees represents the freezing point of water and 100 degrees is the boiling point at standard atmospheric pressure. It is widely used in science and everyday measurements for temperature values.
Kelvin (K): Kelvin is the SI base unit for temperature, starting at absolute zero (-273.15°C). It measures thermodynamic temperature where zero kelvin means no thermal energy. It used mostly in physics and engineering.
Conversion FAQs
Why do we add 273.15 to convert Celsius into kelvin?
The kelvin scale starts at absolute zero, which is -273.15°C. Since Celsius scale zero is at water’s freezing point, adding 273.15 shifts the temperature reference so the kelvin scale begins at absolute zero, making temperatures positive and absolute.
Can the kelvin temperature be negative?
No, kelvin cannot be negative. It starts at absolute zero, the lowest possible temperature where particles have minimal thermal motion. Negative kelvin values do not exist physically, so kelvin values are zero or positive only.
Is 21°C a warm temperature in kelvin?
Yes, 21°C converts to 294.15 K, which is within room temperature range. It is comfortable for humans and typical for indoor environments, indicating neither hot nor cold extremes.
How accurate is the conversion formula for high temperatures?
The formula K = °C + 273.15 is exact for all temperatures, including very high ones. Since both scales are linear and directly offset, the formula remains accurate without approximation errors.
Does the kelvin scale affect weather reports or only scientific measurements?
Kelvin is mostly used in scientific contexts because it starts at absolute zero and avoids negative values. Weather reports commonly use Celsius or Fahrenheit, but kelvin is crucial for physics, chemistry, and engineering to measure absolute temperatures.