What's the Difference Between Candela, Lux, and Lumens?

Comparison: Candela, Lumens, and Lux

When you buy a flashlight or led bulb, you might notice that the packaging includes information about the light output. The three units most often used to measure light output are Candela (cd), Lux (lx), and Lumens (lm).

All three of these units are light intensity measures over a given area. Candela and Lux measure the intensity of visible light, while Lumens measure the total output of a light source. To put it simply:

  • Candela is the unit used to describe the brightness of a light source in a given direction.
  • Lux is the unit measuring the amount of light that hits a surface.
  • Lumens are the unit used to describe the total output of light from a source.
Light output test

The higher the lumen rating, the brighter the light will be.


Lumen is the brightness of light that comes from an led bulb or flashlight; it is used to describe the intensity of a light beam. When choosing a flashlight, it is important to consider the lumen output to ensure you get the level of brightness you need.

For example, a flashlight delivers 1 cd of illumination at any beam angle and 12.5 lm of luminous flux. The same 1 cd source will give 6.25 lumens if you half-cover the lamp. A standard 45 W LED bulb emits approximately 450 lumens.

So whenever you see a flashlight advertised as having a certain number of lumens, it tells you how much light will be produced. The next thing to consider is the beam angle which will tell you how wide or narrow the light beam will be.

A wide beam angle is suitable for general lighting, while a narrow beam angle is suitable for task lighting.

Maytown - What is lumen ?
Maytown - Lux

The higher the lux value, the brighter the light.


Lux is a standard of the light intensity visible to the human eye. It is measured in lumens per square meter.

A few factors affect how much Lux is needed in a given area. These include the activity level, the type of work being performed, and the amount of natural light present.

An office environment should generally have a minimum of 500 lux of light. This can be achieved with a combination of natural and artificial light.

Lux values can also determine the amount of light needed in other settings, such as schools, hospitals, and factories. The right lighting level is essential to maintain safety and productivity in these environments.

So, the next time you are experiencing how bright light should be, think in terms of Lux.


The word "candle" comes from the Latin word candēla, which means "torch." Candela originally referred to a unit of measure that equals the light emitted by one candle. The term was later used to refer to a unit of luminous intensity. The modern unit of measurement for luminous intensity is the Candela.

One Candela is the light emitted from a candle with a flame area of one square centimeter.

A 50 watts of fluorescent bulb will be 270 cd, and if you narrow it down to 20 degrees, the value will be about 36000cd, which is high.

Candela's unit is used in scientific and technical fields such as lighting, photometry, and astronomy. It is also used in the field of medicine to measure the intensity of light therapy.

Maytown - Candela

Lumen Vs. Candela Vs. Lux - How do They Relate With Each Other?

Lumen, Lux, and Candela are all measurement units used to describe the amount of light emitted by a given object. Whenever you see these units of measurement, it's important to know which one is being used to accurately interpret the data.

Lumen Vs. Candela Vs. Lux

Light Clarification - Maytown

Unit Of Light

Lumens measure the total light output of a given light source. A lumen unit is essential when you want to know the overall brightness of a given light source.

Candela measures the luminous intensity or the brightness of a particular light beam. The unit is practical when you need to know how bright a particular beam of light is.

Lux measures the intensity of light hitting a surface and tells you how much of that light reaches the desired surface. Simple math regulates the difference between the three units:

1 Candela = 12.57 Lumens
The higher the Candela, the more focused and brighter the light will be in a particular direction. And if a light emits 12.57 lumen, it has a candela value of one.

One lumen equals one Lux per square meter.
A 100 lux spotlight will produce the same amount of light as a 100 lumen flashlight shining on a one square meter surface from a distance of one meter.

To produce more light on a given surface (i.e., increase the Lux), you either have to increase the number of lumens emitted by the light source or decrease the distance between the light source and the surface.

Lumens and Watts: How They Relate With Each Other?

The difference between the two units is that lumens (lm) measure the amount of light output, whereas watts (W) measure the amount of energy used. So, a higher lumen rating means a brighter light. Also higher the Wattage, the more heat it emits.

To give you a clearer idea, let's look at an example:

  • A 40-watt LED bulb will produce around 600 lumens
  • The lumen output for the 60-watt bulb is 800
  • The lumen output for the 12-watt bulb is 150
  • A 1600 lumen LED bulb will produce approximately the same light as a 100-watt incandescent bulb
light bulb

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