Convert Between Units of Luminous Intensity
Luminous intensity measures the amount of visible light emitted in a particular direction, and its SI unit is the candela (cd). It appears in lighting design, photometry, and optical specifications. Luminous intensity is directional, which distinguishes it from luminous flux (lumens) that measures total light output. Converting luminous intensity units helps when comparing fixture specifications and photometric data.
About Luminous Intensity Conversions
Helpful context and notes for converting Luminous Intensity units.
Lighting specs can be confusing because several related quantities are used together: candela (cd) for intensity in a direction, lumen (lm) for total flux, and lux (lx) for illuminance on a surface. The same lamp can have high lumens but low candela in a specific direction depending on optics and beam shape. When converting, confirm which quantity you actually need. Mixing lumens and candelas is a common source of wrong comparisons when shopping or designing lighting layouts.
Practical tip: if your goal is brightness on a work surface, you usually care about illuminance (lux), which depends on distance and beam distribution, not just candela alone. If you are comparing beam intensity for a spotlight or signaling application, candela is the right quantity. When specs appear inconsistent, check whether one source is quoting lumens and another is quoting candelas, since they are not directly interchangeable without beam geometry.
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