Candela (cd)
SI base unit of luminous intensity, defined by fixing the luminous efficacy of 540 THz light at 683 lm/W.
What is a candela?
- Symbol
- cd
- Quantity
- Luminous Intensity
- Unit system
- SI
- Definition
- SI base unit of luminous intensity, defined by fixing the luminous efficacy of 540 THz light at 683 lm/W.
- Exact
- Yes, the value is exact by definition
- Source
- SI Brochure, 9th edition (BIPM, 2019)
Common applications
Used for the intensity of lamps, LEDs, traffic signals and vehicle lights in a given direction, and in lighting photometry.
Candela in other luminous intensity units
- 1 cd = 1000 mcdCandela to Millicandela converter
- 1 cd = 1000000 µcdMicrocandela
- 1 cd = 0.001 kcdKilocandela
Candela quick reference
| Candela | Millicandela | Microcandela | Kilocandela |
|---|---|---|---|
| 1 cd | = 1000 mcd | = 1000000 µcd | = 0.001 kcd |
| 10 cd | = 10000 mcd | = 10000000 µcd | = 0.01 kcd |
| 100 cd | = 100000 mcd | = 100000000 µcd | = 0.1 kcd |
| 1000 cd | = 1000000 mcd | = 1000000000 µcd | = 1 kcd |
Where the candela fits
The next smaller luminous intensity unit is the millicandela (mcd). 1 cd = 1000 mcd, and 1 mcd = 0.001 cd.
The next larger luminous intensity unit is the kilocandela (kcd). 1 cd = 0.001 kcd, and 1 kcd = 1000 cd.
Frequently asked questions
- How many millicandelas are in one candela?
- One candela = 1000 mcd (millicandelas).
- How many microcandelas are in one candela?
- One candela = 1000000 µcd (microcandelas).
- How many kilocandelas are in one candela?
- One candela = 0.001 kcd (kilocandelas).