Writing & StyleStyle guide

Degree Symbol and Temperature Formatting

The degree sign participates in different conventions depending on what is being measured. The BIPM SI Brochure places a space between a Celsius temperature value and °C, while plane-angle degree symbols follow the number without a space. The Unicode character identity is U+00B0 DEGREE SIGN.

Quick answer

In SI style, write “30.2 °C” for Celsius temperature, but “30°” for a plane angle.

Key details

Core IssueSI notation uses a space between a temperature value and the unit symbol °C, but no space inside °C; plane-angle degree notation attaches the degree sign directly to the number.
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Important caveats

Angle Boundary

For plane angle, the degree symbol is an exception to the normal number-unit spacing rule and is written directly after the number, such as “30°.”

Further guidance

Character Identity

The Unicode character used for the degree sign is U+00B0 DEGREE SIGN.

Temperature

The SI Brochure writes Celsius temperature with a space between the numerical value and the unit symbol, for example “30.2 °C,” with no space between ° and C.

Sources and evidence

Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.

  1. The International System of Units (SI), 9th edition, version 4.01 (opens in a new tab)Bureau International des Poids et Mesures · SI conventions for unit symbols, Celsius temperature spacing, angle-degree notation, and multiplication notation
  2. Latin-1 Supplement — Unicode Names List (opens in a new tab)Unicode Consortium · Unicode character identities for degree sign, plus-minus sign, and multiplication sign

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