Lumens vs. Candelas

While lumens measure the total brightness of a flashlight, candelas focus on the beam intensity and throw. In simpler terms, lumens are the ‘amount’ of light, whereas candelas emphasize how far that light reaches.

At 1Lumen we’ve tested hundreds of flashlights, and 2 aspects we test are the lumens and candelas. However, many people are still confused, because lumens and candelas are 2 different aspects.

In short: What are lumens?

What is a lumen?

In simple terms, a lumen is the overall “quantity” of light produced by a light source. So for flashlights, we measure all the light leaving the flashlight. Most of our reviewers do this inside a homemade integrating sphere, and others use something, called a lumen tube.

At 1Lumen.com, we use the term lumens, but you might also come across the term “Luminous flux” on the internet, which essentially means the same thing. But, in everyday conversations about flashlights, people typically use the term lumens instead of luminous flux. And that’s the reason why we use Lumens instead of luminous flux. Also, we use the abbreviation of lumens, namely lm.

If you want to know how bright X amount of lumens is, check out our Flashlight Brightness Guide

In short: What are Candelas?

What is a candela?

When we review a flashlight, we test Candelas. The abbreviation of candelas is “cd“, which is a unit of measurements to describe the intensity of the beam in a single direction. With candelas you should think about how far a light beam can travel. We measure the most intense spot in the beam with a luxmeter, to calculate the maximum beam distance, measured in Candelas.

The higher the number of candelas, the farther the beam can reach.

What’s the difference between Lumens and Candelas

Lumens and beam distance (candelas) are distinct factors in a flashlight’s performance. Imagine having 2 different flashlights, with both the same amount of lumens. You would still not know which of the 2 can shine farther.

Perhaps this example can help you:

Take two Maglite 3D flashlights with 50 lumens each. Now, remove the head of 1 Maglite, and tighten the beam on the other. Both flashlights still produce 50 lumens, but the one with the head removed does not reach as far as the one with the tightened beam.

The tightly focused beam wins, even though both having the same lumen output!

The following features influence the beam distance of a flashlight. And often it’s a combination of several of these factors to achieve the farthest beam:

1. The size of the reflector (the bigger the reflector, the farther a beam can travel)
2. The size of the LED die
3. The type of TIR optic (there are many TIR optics ranging from 140 degrees width, to 10 degrees, the narrower, the better.
4. The divergence of the beam
5. The type of light source (LEP flashlights can throw farther than LED flashlights, even with the same flashlight dimensions).

Let’s get into some more specifics.

Let’s compare the Weltool W4 Pro (an LEP flashlight with only 550 lumens) to an Acebeam X75 with 80,000 lumens. Which flashlight do you think has a longer beam distance? Surprise, surprise, it’s the Weltool W4 Pro, with less than 1% of the lumen output.

In this example, beam focus (divergence) and design play a more significant role in distance than lumens alone. The much smaller Weltool can reach 3351 meters, while the Acebeam X75 can reach only 889 meters.

Please keep that in mind!

Here’s an example on how the beam on a Weltool W4 Pro looks like compared to the beam of a 80,000 lumen Acebeam X75.

Here is a useful overview of candelas in relation to beam distance.

Keep in mind that 4 times the candelas, doubles the distance in meters. So, if you need your flashlight to shine twice as far, you need to increase the beam intensity by 4.

Note: Sometimes you can see the following abbreviations “kcd” (= 100,000 cd) or “mcd” (= 1,000,000 cd).

Candelas	Meters	Yards	Miles
1,000 cd	63 m	69 yd	0.04 mi
2,000 cd	89 m	98 yd	0.06 mi
3,000 cd	110 m	120 yd	0.07 mi
5,000 cd	141 m	155 yd	0.09 mi
7,000 cd	167 m	183 yd	0.10 mi
10,000 cd	200 m	219 yd	0.12 mi
30,000 cd	346 m	379 yd	0.22 mi
50,000 cd	447 m	489 yd	0.28 mi
75,000 cd	548 m	599 yd	0.34 mi
100,000 cd (100kcd)	632 m	692 yd	0.39 mi
200,000 cd	894 m	978 yd	0.56 mi
300,000 cd	1095 m	1198 yd	0.68 mi
500,000 cd	1414 m	1547 yd	0.88 mi
600,000 cd	1549 m	1694 yd	0.96 mi
700,000 cd	1673 m	1830 yd	1.04 mi
1,000,000 cd (1 Mcd )	2000 m	2187 yd	1.24 mi
1,200,000 cd	2191 m	2396 yd	1.36 mi
1,400,000 cd	2366 m	2588 yd	1.47 mi
1,500,000 cd	2449 m	2679 yd	1.52 mi
1,700,000 cd	2608 m	2852 yd	1.62 mi
2,000,000 cd	2828 m	3093 yd	1.76 mi
2,500,000 cd	3162 m	3458 yd	1.96 mi
3,000,000 cd	3464 m	3788 yd	2.15 mi
4,000,000 cd	4000 m	4374 yd	2.49 mi

You can see that 1 million candelas equals a beam distance of 2,000 meters. And if you want to reach 4,000 meters, you need 4 million candelas.

Here’s what the Flashlight Wiki explains:

An actual distance for throw can be directly calculated from the candela value and will be given in meters. The FL-1 standard does just this by providing a light intensity reading in candela and converting this to throw in meters by calculated the distance at which the light will generate 0.25 lux. Throw is just the square root of the light intensity in candela divided by 0.25 lux which gives meters.

FAQ: questions

• How do you convert lumens to candelas?

  You can’t convert lumens to candelas (with a few exceptions). Lumens are tested in a integrating sphere, while candelas are tested from a distance of 5-30 meters. The only exception where you could use the data from the lumen measurement, is when the testing was done with a Goniometer. Unfortunately, due to the distance from the sensor to the light source, this measurement is untrustworthy for most flashlights when it comes to candelas.

• Is candela more important than lumens?

  It depends what you want to use the flashlight for. If you need a light beam to reach far, you need to pay attention to maximum amount of candelas. If you need a bright flashlight, that doesn’t need to reach farther than a few hundred yards, you need to pay more attention to lumens.

• How do you measure candelas?

  To determine candelas, you need 2 key measurement. First, the distance between the Lux meter and the light source, and second, the Lux intensity measured at that distance. For example: if you measured 50 lux at 5 meters distance, the calculation is Distance x Distance x Lux = 5*5*50 = 1250 cd.
  In another scenario, if you measured 300 lux at 10 meters, the formula would be Distance (10m) x Distance (10m) x Lux (300 lux) = 10*10*300 = 30,000 cd