40 kelvin equals -233.15 degrees celsius.
The conversion from kelvin to celsius is done by subtracting 273.15 from the kelvin value. Since kelvin starts at absolute zero, which is -273.15°C, you simply adjust the scale by this amount to find the temperature in celsius.
Conversion Tool
Result in celsius:
Conversion Formula
The formula for converting kelvin (K) to celsius (°C) is:
°C = K – 273.15
This works because the kelvin scale starts at absolute zero, the lowest possible temperature, set at 0 K. The celsius scale sets the freezing point of water at 0°C, which corresponds to 273.15 K. Therefore, subtracting 273.15 from any kelvin value gives the celsius temperature.
Example calculation for 40 K:
- Start with 40 kelvin.
- Subtract 273.15: 40 – 273.15 = -233.15.
- So, 40 K equals -233.15 °C.
Conversion Example
- Convert 100 kelvin to celsius:
- Subtract 273.15 from 100.
- 100 – 273.15 = -173.15 °C.
- The temperature is -173.15 degrees Celsius.
- Convert 273.15 kelvin to celsius:
- Subtract 273.15 from 273.15.
- 273.15 – 273.15 = 0 °C.
- This is the freezing point of water in celsius.
- Convert 310 kelvin to celsius:
- Subtract 273.15 from 310.
- 310 – 273.15 = 36.85 °C.
- This is roughly normal human body temperature.
- Convert 0 kelvin to celsius:
- Subtract 273.15 from 0.
- 0 – 273.15 = -273.15 °C.
- This is absolute zero, the coldest possible temperature.
Conversion Chart
| Kelvin (K) | Celsius (°C) |
|---|---|
| 15.0 | -258.15 |
| 20.0 | -253.15 |
| 25.0 | -248.15 |
| 30.0 | -243.15 |
| 35.0 | -238.15 |
| 40.0 | -233.15 |
| 45.0 | -228.15 |
| 50.0 | -223.15 |
| 55.0 | -218.15 |
| 60.0 | -213.15 |
| 65.0 | -208.15 |
Look at the kelvin value in the left column, find the corresponding celsius value on the right. The table helps to quickly check conversion without calculation, useful when you need rough estimates or comparison.
Related Conversion Questions
- What is 40 kelvin in degrees celsius exactly?
- How can I convert 40 K to celsius by hand?
- Is 40 kelvin above or below freezing point in celsius?
- What temperature does 40 kelvin represent in celsius scale?
- Why does 40 K equal negative celsius temperature?
- How cold is 40 kelvin compared to room temperature in celsius?
- Can 40 kelvin be expressed as degrees celsius easily?
Conversion Definitions
Kelvin: Kelvin is a temperature scale starting at absolute zero, the lowest limit where particles have minimum thermal motion. Zero kelvin equals -273.15 degrees celsius. The scale is used in science, especially physics and thermodynamics, for measuring absolute temperatures.
Celsius: Celsius is a temperature scale based on the freezing point of water at 0°C and boiling point at 100°C, at standard atmospheric pressure. It is widely used in everyday life and science to express temperatures relative to water’s physical properties.
Conversion FAQs
Why does subtracting 273.15 convert kelvin to celsius?
Because the kelvin scale starts at absolute zero (0 K), which corresponds to -273.15°C, subtracting 273.15 shifts the kelvin value down to the celsius scale. This aligns the scales so freezing and boiling points of water match typical celsius values.
Can kelvin temperature ever be negative?
No, kelvin cannot be negative because it starts at absolute zero, the theoretical lowest temperature possible. Temperatures below 0 K do not exist in physics as it would imply negative thermal energy.
Is 40 kelvin a common temperature in daily life?
No, 40 kelvin is extremely cold compared to everyday temperatures. It equals -233.15°C, far below freezing and typical environmental conditions. Such temperatures are usually found in laboratory or space environments.
How precise is the conversion between kelvin and celsius?
The conversion is exact mathematically, since it only involves subtracting 273.15. However, physical measurements might have uncertainties, but the formula itself is precise and universally accepted.
What types of scientific measurements use kelvin instead of celsius?
Kelvin is preferred in scientific fields like physics and chemistry where absolute temperature matters, such as thermodynamics or cryogenics. It avoids negative numbers and simplifies formulas related to energy and particle motion.