Instant Temperature Unit Converter: Convert from Celsius to Fahrenheit, and More

Use our instant temperature unit converter to convert from Celsius to Fahrenheit, Kelvin to Fahrenheit, Fahrenheit to Celsius, and so on. Simply choose the appropriate unit, and then place the temperature value you would like to convert in the input field and see the instant conversion.

What is the Purpose of a Temperature Unit Converter?

A temperature unit converter is used to translate temperature values between different scales so that users can compare, calculate, or present temperatures in the unit they need. Temperature unit converters are used for example in science, engineering, cooking, travel, weather reporting, and everyday tasks where different regions or disciplines use different temperature scales.

Accurate temperature conversion prevents errors such engineering miscalculations, incorrect oven settings, and improve clarity.

Why Accurate Temperature Measurement Matter

The importance of accurate temperature measurement cannot be overemphasized. Take the case of industrial process control of chemical reactions, where temperature is one of the most frequently used process measurements. Almost all the chemical processes and reactions are temperature-dependent and it is not rare, in chemical plants, where temperature is used as the only indication of the progress of the process.

In applications where temperature is critical to the reaction, a considerable loss of product may result from incorrect temperatures, and in some instances, the loss of control of temperature can result in catastrophic plant failure.

Instrumentation also can be temperature-dependent, requiring careful design or temperature correction, which can determine the choice of the measurement device. 

Temperature dependent properties and constants include resistance, dielectric constant, and the magnetic permeability and susceptibility (of paramagnetic salts).

Other temperature sensitive phenomena include linear and volume expansion of solids and gases, the generation of the Seebeck (thermoelectric EMF) by thermocouples and the generation of Johnson (thermal) white noise by resistors.

Walk with me, as I discuss the various temperature scales, and their relationships to each other.

Basic Concepts of Temperature

What is Temperature?

Temperature is the measure of the average molecular kinetic energy or heat energy within a substance. It is the state of agitation, both lateral and rotational oscillation, of the molecules of the medium.

The higher the temperature of a body, the greater the vibrational energy of its molecules and the greater is its potential to transfer this molecular kinetic energy to another body.

Temperature is the potential to cause heat to move from a point of higher temperature to one of lower temperature. The rate of heat transfer is a function of that temperature difference.

Temperature Units

The three temperature scales commonly used to measure the relative hotness or coldness of a material are:

• Fahrenheit (°F) attributed to Daniel G. Fahrenheit, 1724).
• Celsius (°C) attributed to Anders Celsius, 1742).
• Kelvin (K), which is based on the Celsius scale, and is mainly used for scientific work.

The Rankine scale (°R), based on the Fahrenheit scale is less commonly used.

Scientific temperature measurements are generally performed using the Celsius (centigrade) or Kelvin scales. Absolute zero (thermodynamic zero) occurs at 0 K, or -273.15 °C. That is, K = °C + 273.15.

While most countries in the world use Celsius scale for ordinary things such as cooking and weather reports, use of the Fahrenheit scale is dominant in the United States for these applications.

The nominal boiling and freezing temperatures of water were originally taken as the two calibration points for linear temperature scales; 100° and 0° are those respective temperatures in the Celsius scale, and 212° and 32° are boiling and freezing temperatures in the Fahrenheit scale. You can derive a conversion formula between °F and °C:

°C = 0.55556(°F – 32)

The Fahrenheit scale is based on three reference points originally chosen by Daniel Gabriel Fahrenheit in 1724:

• 0 °F: a cold mixture of ice, water, and salt (ammonium chloride or sea salt) – his zero reference.
• 32 °F: the temperature at which pure water freezes (ice-water equilibrium).
• 96 °F: approximately human body temperature in Fahrenheit’s original scale (later adjusted so that normal body temperature is about 98.6 °F.

Presently, the scale is defined relative to the Celsius scale and the international Kelvin scale: 32 °F ≈ 0°C, and a 1 °F difference equals 5/9 of a 1°C difference.

The Celsius scale is based on the freezing point and the boiling point of pure water at sea level.

The Kelvin and Rankine scales are referenced to absolute zero, which is the temperature at which all molecular motion ceases, or the energy of a molecular is zero.

The temperature of the freezing and boiling points of water, decrease as the pressure decreases, and changes with the purity of the water.  

Temperature Units Conversion Formulas:

• Convert Celsius to Fahrenheit: F = C x 9/5 + 32
• Convert Fahrenheit to Celsius: C = (F – 32) x 5/9
• Convert Celsius to Kelvin:  K= C + 273.15
• Convert Kelvin to Celsius: C = K – 273.15
• Convert Fahrenheit to Kelvin: K = (F – 32) x 5/9 + 273.15
• Convert Kelvin to Fahrenheit: F = (K – 273.15) x 9/5 + 32
• Convert Fahrenheit to Rankine: R = F + 459.67
• Convert Kelvin to Rankine:  R = 9/5 x K
• Convert Rankine to Kelvin: K = R x 5/9

Precision Notes:

• Keep sufficient precision for intermediate steps (use 273.15 exactly where relevant).
• Choose the significant figures that are appropriate to the context (weather vs. laboratory measurements).  
• Keep an eye on the floating-point rounding when you are chaining conversions.

Table 1.0: Comparison of Temperature Scales

	Kelvin (K)	Celsius (°C)	Fahrenheit (°F)	Rankine (°R)
Absolute zero	0	-273.15	-459.67	0
Boiling point (O2)	90.19	-182.96	-297.33	162.34
Zero Fahrenheit	255.37	-17.78	0	459.67
Ice point	273.15	0	32	491.67
Steam point	373.15	100	212	671.67
Freezing point of silver	1234.93	961.78	1763.20	2222.87

Worked Examples:

1. What temperature in °F corresponds to 450K?

Solution:

°C = 450K – 273.15 = 176.85

°F = 176.85 x 9/5 + 32 = 350.33 °F

2. What is the equivalent temperature of -63 °F in °C?

Solution:

°C = (F – 32) x 5/9 = (-63 – 32) x 5/9 = -52.2 °C

3. Convert -273.15 °C to Kelvin

Solution:

K = -273.15 + 273.15 = 0 K (absolute zero)

4. Convert 285 K to °R and 550 °R to K

Solution:

• °R = 285 x 9/5 = 513 °R
• K = 550 x 5/9 = 305.6 K

Conclusion

Temperature unit converters make it easy for users to compare, calculate, or present temperatures in the unit they need.

By utilizing temperature unit converters, you are able to avoid errors such incorrect values arising from inaccurate unit conversions, which in-turn lead to wrong temperature settings, which can have a detrimental effect especially in temperature dependent systems.

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