Temperature Converter – Convert Between All Temperature Units

Temperature Converter

Convert between temperature units including Kelvin, Celsius, Fahrenheit, Rankine, Reaumur, and Triple point of water.

Temperature Conversion Calculator

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Conversion Formula

1 K = 1 K

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Unit Details

Kelvin

Symbol:

Type:

Absolute scale

The Kelvin is the base unit of temperature in the International System of Units (SI). It is defined by taking the fixed numerical value of the Boltzmann constant k to be 1.380649 × 10^-23 J/K.

Celsius

Symbol:

°C

Type:

Relative scale

The Celsius scale is a temperature scale used by the International System of Units (SI). It is defined by two points: 0°C is the freezing point of water, and 100°C is the boiling point of water at 1 atm pressure.

About Temperature Conversion

History of Temperature Measurement

Temperature measurement has a rich history dating back to ancient civilizations. Early attempts at measuring temperature relied on physical properties that change with heat, such as the expansion of air or liquids. The first thermometers were developed in the 16th and 17th centuries, with notable contributions from Galileo Galilei and Santorio Santorio.

The development of standardized temperature scales began in the 18th century. Daniel Gabriel Fahrenheit created the Fahrenheit scale in 1724, using mercury as the thermometric fluid and defining 32°F as the freezing point of water and 96°F as human body temperature. Anders Celsius introduced the Celsius scale in 1742, originally with 0° as the boiling point of water and 100° as the freezing point, which was later inverted to the modern scale.

Lord Kelvin (William Thomson) developed the absolute temperature scale in 1848, based on the theoretical concept of absolute zero—the point at which all molecular motion ceases. This scale was later named the Kelvin scale and became the foundation for the International System of Units (SI).

Understanding Temperature Scales

Temperature scales can be categorized into relative and absolute scales:

Absolute Scales: These scales start at absolute zero, the theoretical lowest possible temperature. The Kelvin scale is the primary absolute scale used in scientific contexts.
Relative Scales: These scales use arbitrary reference points, such as the freezing and boiling points of water. Celsius and Fahrenheit are the most common relative scales.
Specialized Scales: These include Rankine (an absolute version of Fahrenheit), Reaumur (a historical scale), and the triple point of water (a precise reference point).

Practical Applications of Temperature Conversion

Temperature conversion is essential in numerous fields and everyday situations:

Weather Forecasting: Converting between Celsius and Fahrenheit for international weather reports.
Cooking: Following recipes from different countries that use different temperature scales.
Scientific Research: Converting between Kelvin and Celsius for laboratory experiments and data analysis.
Engineering: Working with temperature specifications in different units for manufacturing processes.
Medicine: Converting body temperature readings between different scales.

How to Use This Converter

Our temperature converter tool allows you to convert between six different temperature units quickly and accurately. Simply enter the value you want to convert, select the original unit, choose the target unit, and click the Convert button. The tool will display the converted value, the conversion formula used, and step-by-step calculations showing how the conversion was performed.

This converter is particularly useful for students, scientists, engineers, chefs, and anyone who needs to work with different temperature scales. All conversions are based on the latest international standards to ensure accuracy.

Frequently Asked Questions

What is absolute zero?

Absolute zero is the lowest possible temperature, at which the thermal motion of particles ceases completely. It is defined as 0 Kelvin, -273.15°C, or -459.67°F. At absolute zero, particles have minimum vibrational motion but retain quantum mechanical zero-point energy.

How do I convert Celsius to Fahrenheit?

To convert Celsius to Fahrenheit, use the formula: °F = (°C × 9/5) + 32. For example, 20°C equals (20 × 9/5) + 32 = 68°F. Conversely, to convert Fahrenheit to Celsius, use: °C = (°F – 32) × 5/9.

What is the difference between Kelvin and Celsius?

The Kelvin and Celsius scales have the same magnitude of temperature units, but different zero points. The Kelvin scale starts at absolute zero (0 K), while the Celsius scale starts at the freezing point of water (0°C). To convert between them: K = °C + 273.15 or °C = K – 273.15.

What is the Rankine scale used for?

The Rankine scale is an absolute temperature scale used primarily in engineering fields in the United States. Like Kelvin, it starts at absolute zero, but uses the Fahrenheit degree as its unit increment. To convert between Rankine and Fahrenheit: °R = °F + 459.67 or °F = °R – 459.67.

What is the Reaumur scale?

The Reaumur scale is a temperature scale proposed by René Antoine Ferchault de Réaumur in 1730. It sets the freezing point of water at 0°Re and the boiling point at 80°Re. It was historically used in Europe, particularly in cheese production and cooking, but has largely been replaced by Celsius.

What is the triple point of water?

The triple point of water is the unique temperature and pressure at which liquid water, solid ice, and water vapor coexist in equilibrium. It occurs at exactly 273.16 K (0.01°C) and a vapor pressure of 611.657 pascals. This point is used to define the Kelvin scale in the International System of Units.

Why do different countries use different temperature scales?

Different temperature scales developed historically in different regions due to various scientific and cultural factors. The Fahrenheit scale became established in English-speaking countries, while Celsius (formerly Centigrade) was adopted in most other nations. The persistence of different scales is largely due to tradition and the costs associated with changing established systems.

How do I convert Kelvin to Fahrenheit?

To convert Kelvin to Fahrenheit, first convert to Celsius: °C = K – 273.15, then convert to Fahrenheit: °F = (°C × 9/5) + 32. The combined formula is: °F = (K – 273.15) × 9/5 + 32. For example, 300 K equals (300 – 273.15) × 9/5 + 32 = 80.33°F.

What is normal human body temperature in different scales?

Normal human body temperature is approximately 37°C (98.6°F). In other scales, this equals 310.15 K, 558.27°R, 29.6°Re, and is about 1.137 times the triple point of water. Note that body temperature can vary slightly between individuals and throughout the day.

Why is Kelvin used in scientific contexts?

Kelvin is used in scientific contexts because it is an absolute temperature scale that starts at true zero (absolute zero). This makes calculations involving temperature differences, thermodynamic relationships, and physical laws much simpler and more accurate. Many fundamental equations in physics and chemistry require temperature to be expressed in Kelvin.

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