Candela (cd) is a standard that has replaced the candle. A wax candle’s luminous intensity is roughly one candela.People discussing lighting sometimes call candela candlepower.In 1979, the General Conference on Weights and Measures (CGPM) adopted this definition of Candela: “The candela (cd) is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.”In the International System of Units (SI), the Candela is a unit of measurement that involves human vision and the light we see emitted. Candela is not the entire amount of light emitted by an object, that refers to lumens. If you look at a laser pointer, it has a high candela (since all the light is pointed in a single direction) and a low lumen count. In SI, the constant Kcd, is equal to 683 lumens per watt.On May 20, 2019 the definition of Candela was refined to a more complex wording (which is why we included the original for clarity):“The candela is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540×1012 Hz, Kcd, to be 683 when expressed in the unit lm⋅W−1, which is equal to cd⋅sr⋅W−1, or cd⋅sr⋅kg−1⋅m−2⋅s3, where the kilogram, meter and second are defined in terms of h, c and Δνcs.”