Centigrade and Celsius are the same scale
There is no math to do here in the way most unit conversions require one, because Centigrade and Celsius are two names for the same temperature scale. A reading of 100 "Centigrade" is exactly 100 degrees Celsius - not an approximation, not a close match, but numerically identical. If you have a value in Centigrade, you already have it in Celsius; this calculator exists mainly to confirm that and to show you the equivalent Fahrenheit and Kelvin readings at the same time.
Why two names exist
"Centigrade" was the original name for the scale devised by Swedish astronomer Anders Celsius in 1742, built around 100 degrees between the freezing and boiling points of water at standard atmospheric pressure (0° and 100° respectively, in the modern orientation). The name comes from Latin centum ("hundred") and gradus ("steps"), reflecting that 100-degree span. In 1948, the 9th General Conference on Weights and Measures (CGPM) formally renamed the scale "Celsius" in honor of its inventor, and to avoid confusion with "centigrade" as a generic term for any 100-part angular or gradient unit used elsewhere in science and surveying. Since then, the modern Celsius scale has been formally defined in relation to the Kelvin scale and absolute zero rather than purely by water's freezing and boiling points, but the practical values you read off a thermometer did not change. Older textbooks, some countries, and some legacy instruments still print "Centigrade," which is why searches for a "Centigrade to Celsius" conversion are common even though no conversion factor is involved.
The only real formula: identity
°C (Celsius) = °C (Centigrade). There is no multiplier or offset. If you also want Fahrenheit or Kelvin equivalents, those do have real formulas, and this calculator computes both automatically alongside the identity result:
- Fahrenheit: °F = °C × 9/5 + 32
- Kelvin: K = °C + 273.15
For example, entering 100 (whether you call it Centigrade or Celsius) returns 100.00 °C, 212.00 °F, and 373.15 K. Entering 0 returns 0.00 °C, 32.00 °F, and 273.15 K.
Reference points worth knowing
Because the number never changes between Centigrade and Celsius, the values below apply equally to both names:
- 0 °C - freezing point of water at sea-level atmospheric pressure (32 °F, 273.15 K)
- 37 °C - approximate average human body temperature (98.6 °F, 310.15 K)
- 100 °C - boiling point of water at sea-level atmospheric pressure (212 °F, 373.15 K)
- -40 °C - the single point where Celsius and Fahrenheit scales cross (-40 °F, 233.15 K)
- 180 °C - a common moderate baking oven temperature (356 °F)
- -273.15 °C - absolute zero, the coldest physically possible temperature (0 K, -459.67 °F)
Where you'll still see "Centigrade" used
Some older thermometers, vintage scientific instruments, certain European technical documents, and some non-English usage still label the scale "Centigrade." Weather reports, cooking instructions, and modern scientific literature almost universally say "Celsius" today, per the 1948 CGPM resolution and subsequent SI usage. If you encounter a device or document marked in "Centigrade," you can read it exactly as Celsius without any adjustment.
Frequently asked questions
Is Centigrade the same as Celsius? Yes. They are the same scale with the same zero point (freezing water) and the same 100-degree span to boiling water; "Celsius" is simply the modern, internationally standardized name adopted in 1948.
Do I need to add or multiply anything to convert Centigrade to Celsius? No. There is no conversion factor because it is not a different scale - a Centigrade reading and a Celsius reading are the same number.
Why do some old thermometers say "Centigrade" instead of "Celsius"? They predate the 1948 renaming, or were manufactured in a period/region where the older name remained common; the markings still correspond exactly to today's Celsius scale.
How is Centigrade different from Fahrenheit or Kelvin? Those are genuinely different scales with different zero points and step sizes, so real formulas apply: °F = °C × 9/5 + 32, and K = °C + 273.15. Centigrade-to-Celsius has no such formula because it isn't a scale change.
Is "centigrade" ever used to mean something other than temperature? Yes - in surveying and some scientific contexts, "centigrade" can refer to a gradian, a 100-part division of a right angle, unrelated to temperature. This calculator addresses the temperature-scale meaning, which is by far the more common search intent.