Celsius to Kelvin

What is Celsius to Kelvin Conversion?

Converting Celsius to Kelvin is common in education, science, and many technical fields. The Kelvin scale is an absolute temperature scale, meaning it starts at absolute zero—the coldest possible temperature where all molecular motion stops.

Why You Need This Converter

Kelvin is used in many contexts:

• Education - Physics and chemistry courses often require Kelvin for calculations
• Science - Research papers and scientific data frequently use Kelvin
• Technology - Color temperature for lighting and displays is measured in Kelvin
• Everyday curiosity - Understanding absolute temperature and how cold things can get

The Simple Conversion

Unlike other temperature conversions, Celsius to Kelvin is straightforward: K = °C + 273.15. Both scales use the same degree size—they only differ in their zero points. Water freezes at 0°C (273.15 K) and boils at 100°C (373.15 K).

About the Kelvin Scale

Kelvin is named after Lord Kelvin, a 19th-century physicist. It's the SI (International System) unit for temperature. Note that Kelvin uses no degree symbol—we write "300 K" not "300°K".

How to Use the Celsius to Kelvin Converter

Conversion Steps

1. Enter Celsius temperature - Type your value in the left field
2. Read Kelvin result - The conversion appears on the right
3. Copy for your work - Use the copy button to save the result

Common Temperature Conversions

• -273.15°C = 0 K - Absolute zero (coldest possible)
• -40°C = 233.15 K - Extremely cold
• 0°C = 273.15 K - Water freezing point
• 20°C = 293.15 K - Room temperature
• 37°C = 310.15 K - Body temperature
• 100°C = 373.15 K - Water boiling point

Negative Celsius Values

The converter handles negative Celsius temperatures. Remember that Kelvin cannot be negative—the lowest possible value is 0 K. Any Celsius temperature above -273.15°C converts to a positive Kelvin value.

Color Temperature Note

When dealing with light bulbs or displays, color temperature is expressed in Kelvin. Warm light is around 2700-3000 K, neutral is 4000 K, and cool/daylight is 5000-6500 K.

Converter Features

Simple and Accurate

The converter uses the exact offset of 273.15 defined by the SI system, providing precise results for any input value.

Instant Calculation

Results update in real-time as you type. This allows quick verification of multiple temperatures without clicking buttons.

Useful Reference Points

The reference section shows important temperatures in both scales:

• 0 K (-273.15°C) - Absolute zero
• 273.15 K (0°C) - Ice point
• 293.15 K (20°C) - Room temperature
• 373.15 K (100°C) - Steam point

Bidirectional Conversion

Use the swap button to convert Kelvin back to Celsius. This flexibility helps when checking calculations or converting results from different sources.

Copy Functionality

One-click copy puts the converted value on your clipboard. Paste directly into calculators, documents, or messages without retyping.

Frequently Asked Questions

What is the formula to convert Celsius to Kelvin?

The formula is simply K = °C + 273.15. Add 273.15 to any Celsius temperature to get the Kelvin equivalent.

Why is 273.15 the conversion number?

Absolute zero (0 K) equals -273.15°C. This offset represents the difference between the Kelvin scale's zero point (absolute zero) and the Celsius scale's zero point (water freezing temperature).

Why doesn't Kelvin use a degree symbol?

Kelvin measures absolute thermodynamic temperature, not relative degrees from an arbitrary point. The SI system specifies writing "K" without the degree symbol to reflect this fundamental difference.

Can Kelvin be negative?

No. Kelvin is an absolute scale starting at absolute zero (0 K). Negative Kelvin temperatures are physically impossible as they would represent less than zero molecular motion.

What is room temperature in Kelvin?

Standard room temperature of about 20°C equals 293.15 K. A comfortable indoor temperature of 25°C equals 298.15 K.

When would I use Kelvin instead of Celsius?

Use Kelvin for scientific calculations, physics homework, chemistry problems, or when working with color temperature for lighting and photography.