0 mcd equals 0 lumens. Since millicandela (mcd) measures luminous intensity and lumen measures luminous flux, converting zero intensity naturally results in zero flux.
Luminous intensity in millicandelas and luminous flux in lumens relate through the solid angle over which the light spreads. When the intensity is zero, no light output exists, so the lumen value is also zero. This conversion assumes uniform light distribution over a steradian.
Conversion Tool
Result in lumens:
Conversion Formula
The formula to convert millicandelas (mcd) to lumens (lm) is:
Lumens = mcd ÷ 683
This formula works because candela (cd) is the SI unit for luminous intensity, and lumen (lm) measures luminous flux. Since 1 cd equals 1 lm per steradian, and 1 mcd is 1/1000 of a cd, the conversion involves dividing the mcd value by 683, which is the luminous efficacy constant of monochromatic light at 555 nm.
Step-by-step example:
- Given 500 mcd
- Convert to cd: 500 mcd = 0.5 cd
- Calculate lumens: 0.5 cd ÷ 683 ≈ 0.000732 lm
Conversion Example
- Example 1: 1000 mcd to lumens
- 1000 mcd is 1 cd (because 1000 mcd = 1 cd)
- Lumens = 1 ÷ 683 ≈ 0.001465 lm
- Result: 0.001465 lumens
- Example 2: 250 mcd to lumens
- 250 mcd equals 0.25 cd
- Lumens = 0.25 ÷ 683 ≈ 0.000366 lm
- Result: 0.000366 lumens
- Example 3: 50 mcd to lumens
- 50 mcd equals 0.05 cd
- Lumens = 0.05 ÷ 683 ≈ 0.0000732 lm
- Result: 0.0000732 lumens
- Example 4: 5 mcd to lumens
- 5 mcd equals 0.005 cd
- Lumens = 0.005 ÷ 683 ≈ 0.00000732 lm
- Result: 0.00000732 lumens
Conversion Chart
The chart below displays mcd values from -25.0 to 25.0 and their corresponding lumens. Negative values indicate theoretical or reversed intensity which physically may not be meaningful but shown for mathematical completeness. To use the chart, find the mcd value in the left column and read across to find lumens after dividing by 683.
| mcd | Lumens |
|---|---|
| -25.0 | -0.03662 |
| -20.0 | -0.02929 |
| -15.0 | -0.02197 |
| -10.0 | -0.01465 |
| -5.0 | -0.00732 |
| 0.0 | 0.00000 |
| 5.0 | 0.00732 |
| 10.0 | 0.01465 |
| 15.0 | 0.02197 |
| 20.0 | 0.02929 |
| 25.0 | 0.03662 |
Related Conversion Questions
- How many lumens are in 0 mcd of light intensity?
- What is the lumen equivalent for zero millicandelas?
- Can 0 mcd produce any measurable lumens?
- Is converting 000 mcd to lumens resulting in zero always accurate?
- Why does 000 mcd equal zero lumens when converted?
- Does 0 millicandela light output affect lumen measurements?
- How to interpret lumen values from 000 mcd readings?
Conversion Definitions
mcd (millicandela): A unit of luminous intensity representing one-thousandth of a candela. It measures the perceived power of light emitted in a particular direction, quantifying how bright a light source appears from a specific angle. Millicandelas are common in low-intensity LED specifications.
Lumens: A unit measuring luminous flux, representing the total quantity of visible light emitted by a source per second. Lumens quantify how much light is emitted overall, regardless of direction, describing the brightness perceived by the human eye across all angles.
Conversion FAQs
Why do we divide by 683 when converting mcd to lumens?
The number 683 comes from the maximum luminous efficacy of monochromatic light at 555 nm wavelength, where the human eye’s sensitivity peaks. The division converts luminous intensity (cd) into luminous flux (lm) by accounting for human eye response and standard photometric units.
Can negative mcd values be converted to lumens?
Negative mcd values are not physically meaningful because luminous intensity cannot be negative. However, mathematically, converting negative values by the formula results in negative lumens, representing an invalid or theoretical scenario rather than practical light measurements.
Does the conversion change if the light source direction changes?
Yes, since mcd measures intensity in a specific direction, changing the direction changes the value. Lumens measure total output over all directions. So, a different direction or beam spread affects the conversion result as the solid angle considered changes.
Is the conversion formula valid for all types of light sources?
The formula assumes uniform light emission and standard photometric conditions. For highly directional or non-uniform sources, the conversion might not perfectly represent actual lumens due to angular distribution differences and spectral variations.
Why is 0 mcd equal to 0 lumens when converted?
Since mcd measures luminous intensity, zero mcd means no light intensity is emitted. Without any light intensity, the total luminous flux (lumens) must be zero, because no light energy is radiated into space.
Last Updated : 04 July, 2025
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Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.