The calorie is not part of the current SI. The SI unit that measures the same quantity is the joule (J). Like all SI derived units, the joule is obtained by mu

The calorie is not part of the current SI. The SI unit that measures the same quantity is the joule (J). Like all SI derived units, the joule is obtained by multiplying or dividing any number of SI base units, without using numeric scaling factors. 1 joule = 1 newton × 1 kilogram = m^2 × kg × s^−2. The calorie measures the same quantity as the joule (energy or work), but 1 calorie = 4.184 joules. SI generally disallows having multiple units that measure the same quantity (e.g. tesla vs. gauss), especially ones that have numerical scaling factors (e.g. 1 bar = 100 kilopascals). Quotes and references: > the kcal is not officially part of the International System of Units (SI), and is regarded as obsolete, having been replaced in many uses by the SI derived unit of energy, the joule (J) -- https://en.wikipedia.org/wiki/Calorie https://en.wikipedia.org/wiki/Calorie > (this page does not contain any mention of the word "calorie") -- https://en.wikipedia.org/wiki/International_System_of_Units https://en.wikipedia.org/wiki/International_System_of_Units > (Section 4: Units outside the SI) (page 29) Examples of other non-SI units: calorie > (page 52) (year 1948) calorie > (Section 2.2: SI derived units) (page 21) SI derived units with special names and symbols: joule | J | N ⋅ m | m^2 ⋅ kg ⋅ s^−2 -- https://physics.nist.gov/cuu/pdf/sp330.pdf https://physics.nist.gov/cuu/pdf/sp330.pdf