Are you looking for a quick and easy way to convert a degree centigrade to celsius? If you have been scratching your head trying to remember the formula or hunting for a celsius centigrade conversion table, we have a major surprise for you: they are the exact same thing!
Yes, you read that correctly. One degree centigrade is equal to one degree Celsius. If a thermometer reads 25 degrees centigrade, it is precisely 25 degrees Celsius. There is no complex arithmetic, no fraction multiplication, and no addition or subtraction required to convert centigrade to celsius. The conversion ratio is exactly 1:1.
Despite this fundamental simplicity, millions of people search for a celsius to centigrade converter or a centigrade to celsius calculator every year. Why? Because the English language and scientific history have left us with two different names for the exact same temperature scale. In this comprehensive guide, we will dive deep into why these two terms exist, explore the fascinating history of how the name changed in 1948, look at the "hidden" math of the celsius to centigrade formula, and show you how to easily convert these measurements to other scientific scales like Kelvin and Fahrenheit.
The History: Why Do We Have Both "Centigrade" and "Celsius"?
To understand why we have two terms for the same scale, we have to travel back to the 18th century. In 1742, a Swedish astronomer named Anders Celsius proposed a temperature scale based on the properties of water. However, Celsius's original scale was the reverse of what we use today: he set the boiling point of water at 0 degrees and the freezing point of water at 100 degrees! He chose this "upside-down" layout primarily to avoid negative numbers during the freezing-cold Swedish winters.
A year later, in 1743, French physicist Jean-Pierre Christin proposed an inverted version of the scale, setting the freezing point of water at 0 degrees and the boiling point of water at 100 degrees. This "forward" scale was also independently championed by the famous Swedish botanist Carl Linnaeus in 1745, who commissioned a custom "Linnaeus thermometer" to monitor the temperature inside his university greenhouses. Because the scale was divided into 100 equal parts between the freezing and boiling points of water, it was given the name centigrade. This term comes from the Latin words centum (meaning "hundred") and gradus (meaning "steps" or "degrees"). For over two centuries, this scale was universally referred to as the centigrade scale, and temperatures were recorded simply as "degrees centigrade."
So, why did the name change?
By the mid-20th century, the term "centigrade" was causing significant headaches for international standards bodies, particularly in French and Spanish-speaking countries. In those languages, the term centigrade was already used as a unit of angular measurement. Under the decimalized metric system for angles, a right angle is divided into 100 parts called "gradians" (or "grads"). Therefore, a "centigrade" in French could mean one-hundredth of a right angle (or 1/10,000 of a full circle). This was a recipe for confusion in physics and engineering disciplines.
To eliminate this ambiguity and establish a standardized global nomenclature, the 9th General Conference on Weights and Measures (CGPM) met in 1948. They made the official decision to rename the temperature scale. They chose the name Celsius in honor of Anders Celsius, the astronomer who had first conceptualized the 100-step scale. This name change also achieved a beautiful symmetry: it aligned the scale with other major temperature systems of the era, which were all named after their creators, such as Daniel Gabriel Fahrenheit (Fahrenheit), William John Macquorn Rankine (Rankine), and William Thomson, Lord Kelvin (Kelvin).
Even though the change was officially decreed in 1948, old habits die hard. The BBC weather forecasts in the United Kingdom did not fully transition from "centigrade" to "Celsius" until February 1985. Today, "Celsius" is the internationally accepted scientific term, while "centigrade" remains a nostalgic, colloquial variant in English-speaking countries.
The "Celsius to Centigrade Formula": Why the Calculator Is 1:1
Since the two terms refer to the same scale, what does the actual math look like if you want to convert celsius to centigrade or vice versa? Mathematically, the celsius to centigrade formula is:
Temp in Celsius = Temp in Centigrade
This means that any value you have in one is identical to the other. If you are looking at a celsius to centigrade calculator online, the underlying code is the simplest script ever written. It looks something like this:
function convertCelsiusToCentigrade(celsius) { return celsius; }
The program simply takes the input value and displays it as the output. If you plug in 37 degrees Celsius (normal human body temperature), the centigrade to celsius calculator will immediately display 37 degrees centigrade.
While there is no mathematical conversion needed, understanding this direct conversion centigrade celsius equivalence is crucial for reading older scientific papers, historical documents, or vintage weather logs where "centigrade" was the standard notation.
Converting Centigrade and Celsius to Kelvin: Step-by-Step
While converting between Celsius and Centigrade requires no math, the conversion of centigrade to kelvin is a vital process in chemistry, physics, and thermodynamics.
The Kelvin (K) scale is the base unit of temperature in the International System of Units (SI). Unlike Celsius or Fahrenheit, Kelvin is an absolute scale. This means it does not use "degrees." Instead, its starting point is Absolute Zero (0 K), the theoretical point at which all molecular motion ceases and a system has no thermal energy.
Because the size of one unit of Kelvin is exactly equal to the size of one degree Celsius, converting between them is incredibly straightforward. You simply shift the starting point. Absolute zero is equivalent to -273.15 °C. Therefore, to perform a conversion of centigrade to kelvin, you use the following formula:
K = °C + 273.15
(In everyday practical calculations, scientists often round this to K = °C + 273 for simplicity).
Let's look at some step-by-step examples of this conversion:
Example 1: Converting Room Temperature (20 °C) to Kelvin
- Identify the temperature in Celsius: 20 °C
- Apply the formula: K = 20 + 273.15
- Calculate the sum: K = 293.15
- Result: Room temperature is 293.15 K.
Example 2: Converting the Boiling Point of Water (100 °C) to Kelvin
- Identify the temperature in Celsius: 100 °C
- Apply the formula: K = 100 + 273.15
- Calculate the sum: K = 373.15
- Result: The boiling point of water is 373.15 K.
Example 3: Converting a Freezing Winter Day (-15 °C) to Kelvin
- Identify the temperature in Celsius: -15 °C
- Apply the formula: K = -15 + 273.15
- Calculate the sum: K = 258.15
- Result: A freezing winter temperature of -15 °C is 258.15 K.
If you need to go the other way—from Kelvin to Centigrade or Celsius—you simply subtract 273.15 from the Kelvin temperature:
°C = K - 273.15
For example, if a gas is at 300 K, its temperature in Celsius is 300 - 273.15 = 26.85 °C.
Converting Centigrade and Celsius to Fahrenheit: Step-by-Step
In the United States, Liberia, and a few other territories, the Fahrenheit (°F) scale is still widely used for everyday weather, cooking, and body temperature. Converting from Centigrade/Celsius to Fahrenheit is a bit more complex because the scales have different starting points (freezing is 0 °C but 32 °F) and different step sizes (the gap between freezing and boiling is 100 degrees on the Celsius scale, but 180 degrees on the Fahrenheit scale).
The ratio between these step sizes is 180/100, which simplifies to 9/5 (or 1.8). To convert Centigrade/Celsius to Fahrenheit, use this formula:
°F = (°C * 1.8) + 32
Let's look at step-by-step examples of converting Centigrade/Celsius to Fahrenheit:
Example 1: Converting Normal Body Temperature (37 °C) to Fahrenheit
- Identify the temperature in Celsius: 37 °C
- Multiply by 1.8: 37 * 1.8 = 66.6
- Add 32: 66.6 + 32 = 98.6
- Result: Normal body temperature is 98.6 °F.
Example 2: Converting a Hot Summer Day (30 °C) to Fahrenheit
- Identify the temperature in Celsius: 30 °C
- Multiply by 1.8: 30 * 1.8 = 54
- Add 32: 54 + 32 = 86
- Result: A hot day of 30 °C is 86 °F.
To convert Fahrenheit back to Centigrade/Celsius, use the reverse formula:
°C = (°F - 32) / 1.8
Let's convert a baking temperature of 350 °F to Celsius:
- Identify the temperature in Fahrenheit: 350 °F
- Subtract 32: 350 - 32 = 318
- Divide by 1.8: 318 / 1.8 = 176.67
- Result: 350 °F is approximately 176.67 °C.
An interesting piece of science trivia: Is there a temperature where Celsius and Fahrenheit are exactly the same? Yes! At -40 degrees, the two scales cross over. Thus, -40 °C = -40 °F.
Ultimate Temperature Reference Table
To help you visualize these conversions easily without needing a physical centigrade to degrees celsius converter or a manual calculator, here is a complete reference table of critical temperature points across all four major scales:
| Physical Milestone | Centigrade (°C) | Celsius (°C) | Kelvin (K) | Fahrenheit (°F) |
|---|---|---|---|---|
| Absolute Zero | -273.15 | -273.15 | 0.00 | -459.67 |
| Freezing Point of Water | 0.00 | 0.00 | 273.15 | 32.00 |
| Triple Point of Water | 0.01 | 0.01 | 273.16 | 32.02 |
| Room Temperature (Average) | 20.00 | 20.00 | 293.15 | 68.00 |
| Normal Human Body Temp | 37.00 | 37.00 | 310.15 | 98.60 |
| Boiling Point of Water | 100.00 | 100.00 | 373.15 | 212.00 |
Frequently Asked Questions (FAQ)
Is 1 degree centigrade equal to 1 degree Celsius?
Yes, absolutely. They are identical. 1 °C on the centigrade scale represents the exact same temperature and thermal increment as 1 °C on the Celsius scale.
Why was the term "centigrade" replaced by "Celsius"?
In 1948, the 9th General Conference on Weights and Measures decided to change the name to "Celsius" to honor the scale's inventor, Anders Celsius, and to eliminate confusion with the term "centigrade" used as a metric unit of angular measurement (one-hundredth of a right angle, or gradian) in several languages like French and Spanish.
Are there any differences at all between modern Celsius and old Centigrade?
While they are identical for all practical and everyday applications, there is a very tiny, highly pedantic difference in how they are defined in modern science. The old "centigrade" scale was defined purely by two points: the melting point of ice (0 °C) and the boiling point of water (100 °C) at standard atmospheric pressure. Modern Celsius, however, is defined relative to the Kelvin scale and absolute zero. This modern definition means the boiling point of water at standard atmospheric pressure is actually about 99.974 °C, rather than exactly 100 °C. But for 99.9% of human applications, they are completely interchangeable.
How do you write degrees Celsius or centigrade?
The correct symbol is °C. Note that the degree symbol (°) should be immediately followed by the capital letter C, with a space between the numerical value and the degree symbol (e.g., 25 °C). When writing it out in lowercase text, "degrees Celsius" is capitalized because it is named after a person, whereas "degrees centigrade" is kept entirely in lowercase.
Can you convert Celsius to centigrade on a calculator?
Yes, but the result will always be the same as your input. Since the conversion is 1:1, entering any temperature in Celsius will yield the exact same numerical temperature in centigrade.
Conclusion
When it comes down to it, the search for a way to convert a degree centigrade to celsius is a search born of historical linguistic confusion. Once you realize that "Celsius" is simply the modern, internationally standardized name for "centigrade," you can navigate any scientific formula or weather report with total confidence.
While you don't need any complex formulas for a celsius centigrade conversion, you now have the tools, formulas, and knowledge to convert these values into Kelvin and Fahrenheit. Whether you are baking a cake, analyzing a laboratory experiment, or checking the global weather report, understanding these temperature scales is key to unlocking a clearer understanding of the physical world around us.
