candela vs lumens

Candela To Lumens Calculator And How To Use It?

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Hey there! Today I want to talk to you about a topic that might seem confusing at first, but it’s actually very simple and useful. I’m talking about candela to lumens calculator.

You might have seen these terms on some light bulbs or lamps, but do you know what they mean and how they are related? If not, don’t worry, I’m here to explain everything in a clear and easy way. By the end of this post, you will be able to convert between candela and lumens like a pro and choose the right light source for your needs.

So let’s get started!

Candela to Lumens Calculator

Candela to Lumens Converter

Enter the luminous intensity in candela and either the apex angle in degrees or the solid angle in steradians and press the Calculate button to get the luminous flux in lumens:










If you need to convert Lumens to Candela, check out here! You can get all the information you need below!

How to Use an Online Candela to Lumens Calculator

If you don’t want to use a formula or a table, you can use our online candela to lumen calculator to do the conversion for you. 

To use an online candela to lumens calculator, you just need to enter the luminous intensity in candela and the apex angle in degrees, and click on the calculate button. The calculator will show you the luminous flux in lumens.

For example, if you use our calculator and enter a luminous intensity of 1000 candela and an apex angle of 60 degrees, you will get a luminous flux of approximately 840 lumens.

What is Candela and How is it Measured?

Candela is the unit of luminous intensity, which means how bright a light source is in a specific direction. Candela is also known as candlepower, because it was originally based on the brightness of a standard candle. 

To measure candela, you need to know the luminous flux and the solid angle of the light source. Luminous flux is the total amount of light emitted by the source in all directions, measured in lumens. Solid angle is the area of a sphere that the light covers, measured in steradians. 

The formula to calculate candela is:

Φv(lm) = Iv(cd) × Ω(sr)

where Iv is the luminous intensity in candela, Φv is the luminous flux in lumens, and Ω is the solid angle in steradians. 

The solid angle Ω in steradians (sr) is equal to 2 times pi times 1 minus cosine of half the cone apex angle θ in degrees (°):

Ω(sr) = 2π(1 – cos(θ/2))

You can choose either from our calculator. (Solid angle or Apex angle)

What is Lumen and How is it Measured?

Lumen is the unit of luminous flux, which means how much light is emitted by a light source in all directions. Lumen is also known as brightness or light output.

To measure lumen, you need to know the luminous intensity and the solid angle of the light source. Luminous intensity is how bright a light source is in a specific direction, measured in candela. Solid angle is the area of a sphere that the light covers, measured in steradians.

Steradian Angle Explanation
Steradian Angle Explanation

When we turned solid angle into apex angle, then the formula to calculate lumen is:

Φv(lm)  = Iv(cd) × (2π (1 – cos (θ / 2)))

where Φv is the luminous flux in lumens, Iv is the luminous intensity in candela, and (2π (1 – cos (θ / 2))) is the part where we turn solid angle into apex angle.

Why Convert Candela to Lumens?

You might want to convert candela to lumens for different reasons. For example:

– You want to compare the brightness of different light sources that have different beam angles or shapes.

– You want to calculate how much light reaches a surface or an object from a certain distance and direction.

– You want to choose the right light source for your needs based on its efficiency or energy consumption.

Converting candela to lumens can help you find out how much light a source emits in total or how much light it emits per unit area. This can help you decide which light source is more suitable for your purpose.

How to Convert Candela to Lumens Using a Formula

To convert candela to lumen using a formula, you need to know the luminous intensity and the apex angle of the light source. Luminous intensity is how bright a light source is in a specific direction, measured in candela. The apex angle is the angle between two lines that go from the center of the light source to the edges of its beam, measured in degrees.

The formula to convert candela to lumens using an apex angle is:

Φv(lm)  = Iv(cd) × (2π (1 – cos (θ / 2)))

where Φv is the luminous flux in lumens, Iv is the luminous intensity in candela, θ is the apex angle in degrees, and π is approximately 3.14.

For example, if a light source has a luminous intensity of 1000 candela and an apex angle of 60 degrees, its luminous flux is:

Φv (lm) = 1000 cd × (2 × 3.14 × (1 – cos (60 / 2)))

Φv (lm) = 1000 cd × 0.84

Φv (lm) = 820 lm

Candela vs Lumens Conversion Table

Here is a table that shows some common values of candela and their corresponding values of lumens for different apex angles:

CandelaLumens (10°)Lumens (30°)Lumens (60°)Lumens (90°)Lumens (120°)
10.0240.2140.8421.8403.142
100.2392.1418.41818.40331.416
1002.39021.40984.179184.030314.159
100023.909214.094841.7881840.3023141.593
10000239.0942140.9438417.87218403.02431415.927
Candela to Lumens Conversion Table

If you ever wondered How Bright your desired Lumens is, check our “How Bright” page. We have tried to explain all the lumens levels from 200 to 1600 lumens.

Tips and Tricks for Choosing the Right Light Source Based on Candela and Lumens

Here are some tips and tricks for choosing the right light source based on candela and lumens:

candela vs lumens
Candelas and Lumens Explanation

Frequently Asked Questions about Candela and Lumens

Here are some frequently asked questions about candela and lumens:

What is the difference between candela and lumen?

Candela is the unit of luminous intensity, which means how bright a light source is in a specific direction. Lumen is the unit of luminous flux, which means how much light is emitted by a light source in all directions.

How many lumens are in a candela?

There is no fixed answer to this question because it depends on the apex angle of the light source. The formula to convert candela to lumens using an apex angle is:

`Φv (lm) = Iv (cd) × (2π (1 – cos (θ / 2)))`

where Φv is the luminous flux in lumens, Iv is the luminous intensity in candela, θ is the apex angle in degrees, and π is approximately 3.14.

What is the relationship between candela, lumen, and steradian?

Candela, lumen, and steradian are related by the following formula:

Φv (lm) = Iv (cd) × Ω (sr)

where Φv is the luminous flux in lumens, Iv is the luminous intensity in candela, and Ω is the solid angle in steradians.

This formula means that the total amount of light emitted by a source (lumens) is equal to the brightness of the source in a specific direction (candela) times the area of the sphere that the light covers (steradians).

A steradian is a unit of solid angle that measures how much a cone-shaped beam of light spreads out. One steradian is equal to the area of a circle with a radius of one meter on a sphere with a radius of one meter. A full sphere has 4π steradians, which is about 12.57.

For example, if a light source has a luminous intensity of 100 candela and emits light uniformly in all directions, its luminous flux is:

Φv (lm) = 100 cd × 4π sr

Φv (lm) = 100 cd × 12.57

Φv (lm) = 1257 lm

How to Choose the Right Light Source Based on Candela and Lumens

Choosing the right light source based on candela and lumens depends on your purpose and preference. Here are some factors to consider:

  • The size and shape of the area you want to illuminate: If you want to light up a large area evenly, you need a light source with a high lumen value and a wide beam angle. If you want to focus light on a small area or an object, you need a light source with a high candela value and a narrow beam angle.
  • The distance between the light source and the surface or object: The farther away the light source is from the surface or object, the less light will reach it. This is because the light spreads out over a larger area as it travels. To compensate for this, you need a light source with a higher candela or lumen value, depending on the beam angle.
  • The brightness and color of the surface or object: The brighter and lighter the surface or object is, the more it will reflect light and appear brighter. The darker and duller the surface or object is, the more it will absorb light and appear dimmer. To make sure that the surface or object is well-lit and visible, you need a light source with a suitable candela or lumen value, depending on the beam angle.
  • The ambiance and mood you want to create: The brightness and color of the light source can affect how you feel and perceive your surroundings. For example, warm white light can create a cozy and relaxing atmosphere, while cool white light can create a bright and energetic atmosphere. To choose the right light source for your mood, you need to consider its color temperature and color rendering index, which are measured in kelvins and CRI respectively.

Are candela and lumen interchangeable?

No, they are not interchangeable. Candela measures how bright a light source is in a specific direction, while lumen measures how much light a source emits in all directions. They are related by the solid angle of the light beam.

Which one is more important: candela or lumen?

It depends on your purpose and preference. Candela is more important if you want to focus light on a specific direction or spot. Lumen is more important if you want to illuminate a large area evenly. That’s why all the bulbs show lumen values in their specs.

How do I convert candela to lumen or vice versa?

You can use a formula, a table, or our online calculator to convert between candela and lumen. The formula is:

Φv (lm) = Iv (cd) × (2π (1 – cos (θ / 2)))

where Φv is the luminous flux in lumens, Iv is the luminous intensity in candela, θ is the apex angle in degrees, and π is approximately 3.14.

You can also use our online calculator above.

What are some examples of candela and lumen values for common light sources?

Here are some examples of candela and lumen values for common light sources:

Light sourceCandelaLumenBeam angle
Candle112.57360°
Flashlight10084.1860°
LED bulb500420.8960°
Car headlight1500321.1430°
Laser pointer50000.00000120.001°

TL;DR / Conclusion


In this blog post, I explained what candela and lumen are, how they are measured, why they are important, how to convert between them, and how to choose the right light source based on them. I hope you learned something new and useful from this post.

Here are the main points to remember:

  • Candela is the unit of luminous intensity, which means how bright a light source is in a specific direction.
  • Lumen is the unit of luminous flux, which means how much light a source emits in all directions.
  • Candela and lumen are related by the solid angle of the light beam, which is measured in steradians.
  • To convert between candela and lumen, you can use a formula, a table, or our online calculator.
  • To choose the right light source based on candela and lumen, you need to consider the size and shape of the area you want to illuminate, the distance between the light source and the surface or object, the brightness and color of the surface or object, and the ambiance and mood you want to create.

Here is a poem that makes Lumen and Candela’s relationship more memorable:

Lumen and candela are both measures of light
But they are not the same in every sight
Lumen tells you how much light is there
Candela tells you how much light is where

Lumen is the total output of a source
Candela is the intensity of a course
Lumen is the brightness of a beam
Candela is the focus of a stream

Lumen and candela are related by an angle
The smaller the angle, the more they mingle
To convert them, you need to know the solid angle in steradians
Then you can divide or multiply them by this radians

Lumen and candela can help you choose a light source
Depending on your purpose and your resource
Lumen and candela can make a difference in your vision
So learn them well and make a wise decision

Batu

Thank you for reading. If you have any questions or comments, please leave them below. I would love to hear from you. And don’t forget to share this post with your friends who might be interested in lighting. Don’t forget to check our posts about smart lighting, see you next time, and happy lighting!

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Philosophy: We want to make sure that our readers can use smart home products with maximum efficiency. Our ultimate desire in this blog is to ensure our readers use smart home gadgets to make their lives easier, more accessible, and safer.

Batu of CondoChance Team

BSc. Electrical Engineer & MBA
10+ years of industrial experience as an Electrical Engineer

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