# Celsius to Fahrenheit conversion.

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 Celsius Fahrenheit =
How many degrees Fahrenheit in 20.5 degrees Celsius? How to convert 20.5 Celsius to Fahrenheit?

Use our Celsius to Fahrenheit converter to understand:

## What is the formula to convert 20.5 from °C to °F?

Celsius to Fahrenheit formula: [°F] = [°C] × 9⁄5 + 32

The final formula to convert 20.5 Celsius to Fahrenheit is: [°F] = 20.5 × 9⁄5 + 32 = 68.9

### The Celsius scale and the Fahrenheit scale

The discovery of temperature scales is one of the most important pieces of science history in our human lives. It’s hard to imagine how life would be if we could not measure temperature, using temperature scale is so entwined with our day to day lives, deciding what to wear or when to adjust the room AC, in the manufacturing industries we monitor temperature changes using the scales and most of all the health industry relies on measuring body temperature changes for certain medical diagnostics and deductions. The interesting part in all this is that there are two major scales used to measure temperature, the Celsius scale, and the Fahrenheit scale. Many people do not know the difference between the two, countries that use the Celsius scale have troubles relating or converting to the Fahrenheit scale and the same is true for the countries that use the Fahrenheit scale. So let us look into the two temperature scales and see how they differ from each other, to do this a little background information on the two scales is necessary.

### The Celsius scale

The Celsius scale was developed by a very reputable astronomer from Sweden called Anders Celsius. Logically the scale was named after this great astronomer to honor his excellent work. It is the most used method of measuring temperature in the world and as such, it is the SI derived unit of choice scientifically. Most academic institutions teach this scale instead of the Fahrenheit scale.

Interesting fact: before the scale was renamed to honor the Swedish genius, it was call centigrade derived from Latin words centum and gradus which mean 100 and steps respectively.

When referring to a specific temperature on the scale, the term degree Celsius is adopted which is given the symbol notation °C.
The Celsius temperature scales measure temperature and is used as a value to appreciate how hot or cold something is. Normally the scale ranges from 0° for the freezing point of water and 100° for the boiling point of water. Negative values are used for temperatures below freezing point.
There is a relation between the Celsius scale and another one called the Kelvin scale, so often you will notice some conversions from either one of the scales to the other. This relationship is used a lot in thermodynamics chemistry. To convert between the Celsius scale and the Kelvin you use the relation 0 K= −273.15 °C.

### The Fahrenheit scale

From Sweden and astronomy, we go to Germany and physics, the Fahrenheit scale was developed by a German physicist called Daniel Fahrenheit and so the scale was named in honor. Similar to the Celsius scale, the Fahrenheit scale is expressed in degree Fahrenheit, symbolized as °F.

There are many theories on how Daniel Fahrenheit developed his scale. It is said that the physician used the temperature of a solution of brine and defined it as the lower point in the scale, 0 °F. He chose a solution of brine because brine is made up of the quantity of ice and salt. As he worked to develop the scale, he defined the melting point of ice to be 32 °F and he estimated the average human body temperature to be 96 °F, which was later modified by modern scientist to become 98°F when the scale was adjusted. Similar to the Celsius scale, the Fahrenheit scale is defined by two points, the freezing point of water set at 32 °F, and the boiling point of water set at 212 °F. The Fahrenheit scale was mostly used by the United States and its associated states. The rest of the world moved to the Celsius scale.

### The relation between the Fahrenheit scale and the Celsius scale

While both scales measure temperature, scientists concluded that the Celsius scale was more precise that the Fahrenheit scale which brought about the worldwide switch from degree Fahrenheit to degree Celsius. They developed a relation to converting between two, it is given by:

C = (5/9)*(F - 32)

Meaning to convert from one scale to another you would:
Celsius to Fahrenheit: Multiply by 9, divide by 5, and then add 32
Fahrenheit to Celsius: Subtract 32, then multiply by 5, then divide by 9

Interesting fact: The Fahrenheit scale and the Celsius scale are the same at -40 degrees.
This relation can also be used when converting from one scale to the other.