Degree Celsius symbol

A degree sign followed by a capital C, marking a temperature in Celsius.

Also known as: Centigrade

ScientificEveryday & digitalEngineering & technicalStandard profile

Meanings

°C is the SI symbol for the degree Celsius. The SI accepts it alongside the kelvin, defines it as an exactly equal interval, and requires a space before it: 20 °C.

Officially standardisedVerified fact
Denotes the degree Celsius, the SI unit of Celsius temperature, accepted for use with the SI alongside the kelvin.
Contexts: Mathematics
Officially standardisedVerified fact
Is written with a space between the number and the symbol, and with no space inside the symbol: 20 °C, not 20°C or 20° C.
Contexts: Mathematics
Common modern usageVerified fact
Names an interval identical in size to the kelvin, so a temperature difference may be stated in either unit, while the two scales differ in origin by 273.15.
Contexts: Mathematics
Common modern usageVerified fact
Is encoded both as a single character, U+2103 DEGREE CELSIUS, and as a degree sign followed by a capital C — the two-character form being the one normally recommended for text.
Contexts: Software

Visual description

A small raised circle sitting at the height of the capital letters, followed by a capital Latin C drawn as an open curve facing right.

Symmetry: none
Orientation: upright

Commonly confused with: Degree Fahrenheit symbol
Identical in construction and different in scale; a number without its letter is ambiguous and sometimes dangerously so.
Commonly confused with: Speed of light symbol
Both reduce to a bare letter c and appear together in scientific writing.
Commonly confused with: Kelvin symbol
The same interval size, a different origin, and only one of the two takes a degree sign.
Composed of: Degree sign
The degree sign is the first of its two characters.

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

SI base units
Bureau International des Poids et Mesures · retrieved 2026-07-31
The seven base units and their symbols as published by the defining body. A summary page: the SI Brochure remains the full instrument.
Guide for the Use of the International System of Units (SI), NIST Special Publication 811
National Institute of Standards and Technology · retrieved 2026-07-31
A national metrology institute's guidance on applying the SI, including symbol formatting. Authoritative for usage rules in the United States; it interprets the SI rather than defining it.
Celsius
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for origin narrative and for units the SI does not define, never for an official-definition claim.
Unicode Code Chart: Latin-1 Supplement (U+0080–U+00FF)
The Unicode Consortium · retrieved 2026-07-30
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.
The International System of Units (SI), 9th edition
Bureau International des Poids et Mesures · retrieved 2026-07-31
The defining document for SI unit names and symbols, including the capitalisation and spacing rules. It defines units; it says nothing about how a symbol is encoded in a character set, and nothing about non-SI units except where it lists those accepted for use with the SI.
Unicode Code Chart: Letterlike Symbols (U+2100–U+214F)
The Unicode Consortium · retrieved 2026-07-31
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.

Last reviewed 2026-08-01

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Units of measurement and their symbols

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Meanings

°C is the SI symbol for the degree Celsius. The SI accepts it alongside the kelvin, defines it as an exactly equal interval, and requires a space before it: 20 °C.

Officially standardisedVerified fact

Denotes the degree Celsius, the SI unit of Celsius temperature, accepted for use with the SI alongside the kelvin.

Contexts: Mathematics

Officially standardisedVerified fact

Is written with a space between the number and the symbol, and with no space inside the symbol: 20 °C, not 20°C or 20° C.

Contexts: Mathematics

Common modern usageVerified fact

Names an interval identical in size to the kelvin, so a temperature difference may be stated in either unit, while the two scales differ in origin by 273.15.

Contexts: Mathematics

Common modern usageVerified fact

Is encoded both as a single character, U+2103 DEGREE CELSIUS, and as a degree sign followed by a capital C — the two-character form being the one normally recommended for text.

Contexts: Software

Related & commonly confused symbols

Commonly confused with: Degree Fahrenheit symbol
Identical in construction and different in scale; a number without its letter is ambiguous and sometimes dangerously so.
Commonly confused with: Speed of light symbol
Both reduce to a bare letter c and appear together in scientific writing.
Commonly confused with: Kelvin symbol
The same interval size, a different origin, and only one of the two takes a degree sign.
Composed of: Degree sign
The degree sign is the first of its two characters.

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

SI base units
Bureau International des Poids et Mesures · retrieved 2026-07-31
The seven base units and their symbols as published by the defining body. A summary page: the SI Brochure remains the full instrument.
Guide for the Use of the International System of Units (SI), NIST Special Publication 811
National Institute of Standards and Technology · retrieved 2026-07-31
A national metrology institute's guidance on applying the SI, including symbol formatting. Authoritative for usage rules in the United States; it interprets the SI rather than defining it.
Celsius
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for origin narrative and for units the SI does not define, never for an official-definition claim.
Unicode Code Chart: Latin-1 Supplement (U+0080–U+00FF)
The Unicode Consortium · retrieved 2026-07-30
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.
The International System of Units (SI), 9th edition
Bureau International des Poids et Mesures · retrieved 2026-07-31
The defining document for SI unit names and symbols, including the capitalisation and spacing rules. It defines units; it says nothing about how a symbol is encoded in a character set, and nothing about non-SI units except where it lists those accepted for use with the SI.
Unicode Code Chart: Letterlike Symbols (U+2100–U+214F)
The Unicode Consortium · retrieved 2026-07-31
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.

Last reviewed 2026-08-01