Mole symbol

The three letters mol, the SI unit symbol for the mole.

MathematicalScientificQuiet profile

Meanings

mol is the SI symbol for the mole, the base unit of amount of substance — since 2019 a fixed count of exactly 6.02214076 × 10²³ elementary entities.

Officially standardisedVerified fact
Denotes the mole, the SI base unit of amount of substance.
Contexts: Mathematics
Common modern usageVerified fact
Was redefined in 2019 as a fixed number of entities rather than as the number of atoms in twelve grams of carbon-12, severing the last link between amount of substance and mass.
Contexts: Mathematics
Common modern usageVerified fact
Must always be accompanied by a statement of what is being counted — moles of atoms, molecules, ions or electrons — because the unit counts entities without specifying which.
Contexts: Mathematics

Visual description

Three lower-case Latin letters in sequence: an m of two arches, a closed round o, and an l drawn as a single vertical stroke with an ascender.

A fuller structured visual breakdown is not yet documented for this symbol.

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.
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.

Last reviewed 2026-08-01

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Units of measurement and their symbols

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Meanings

mol is the SI symbol for the mole, the base unit of amount of substance — since 2019 a fixed count of exactly 6.02214076 × 10²³ elementary entities.

Officially standardisedVerified fact

Denotes the mole, the SI base unit of amount of substance.

Contexts: Mathematics

Common modern usageVerified fact

Was redefined in 2019 as a fixed number of entities rather than as the number of atoms in twelve grams of carbon-12, severing the last link between amount of substance and mass.

Contexts: Mathematics

Common modern usageVerified fact

Must always be accompanied by a statement of what is being counted — moles of atoms, molecules, ions or electrons — because the unit counts entities without specifying which.

Contexts: Mathematics

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.
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.

Last reviewed 2026-08-01