What Does Lumens Mean On a Flashlight?

With literally thousands of flashlights available in the market to choose from, which one is the brightest? ‘Lumens’ is now probably a familiar term that keeps popping up. By now, you would probably think that the brightest flashlight is one with the highest advertised lumen, but is this really the only factor you should consider?

This article aims to guide you through the thought process when it comes to choosing the most ideal LED flashlight, through a little education.


Lumen vs Lux vs Candela

Before embarking on a hunt for flashlights with the highest lumens, let’s understand what is lumen vs lux vs candela. Its a complicated topic with lots of calculations and theories but I’m just going to try and keep things simple.

Lumen (lm) is a measure of the total light given OUT by a source in all directions.

Our eyes are poor judges of light intensity without looking at the objects it illuminates. How many times do you find yourself judging the brightness of a light source by looking at how bright it illuminates the surroundings? When light bounces off an object and enters our eyes, that is brightness and its measurement is in lux.

Lux is the measurement of brightness over a fixed surface area.

1 lux = 1 lumen per square meter

Alright, that’s as much mathematical formula as this post will contain. So anyways, to increase brightness, you either:

  1. Generate more lumens so that more of it reaches the fixed area
  2. Gather all those lumens radiating from the source that’s going in all directions and send them towards the fixed area

The latter forms a beam.

Candela (cd) is the strength of brightness within a beam of light.

Candela takes into consideration lumens and the angle which the light is being projected. How it relates to lumens and lux is a little complicated, but to keep everything simple, lets imagine you have 2 flashlights, each generating 1000 lumens. The one with a higher candela value is likely a long distance ‘thrower’, much like a spotlight that projects a strong powerful beam that can light up a small area a greater distance away.

The one with a smaller candela value doesn’t focus the lumens as tightly, therefore causing light to ‘spill’ outside of the beam. It will probably not be able to project the light as far as the first flashlight, but it will light up the areas around the beam much better. If the candela value is really low, then it will likely behave like a flood light, illuminating your immediate surroundings.

Getting lost here? This pictorial representation at Gizmodo explains everything above in a single image.

As you can see by now, lumens are not everything. A 1000-lumen flashlight doesn’t tell you how effective it manipulates all that light, or the quality of its focusing optics and reflectors.


What is ANSI NEMA FL-1?

To address the confusion caused by the industry’s exaggerations of ’emitter lumens’, the American National Standards Institute (ANSI), together with the National Electrical Manufacturers Association (NEMA) approved the ANSI-NEMA FL-1 standard, or simply, the FL 1 standard.

Here’s a look at the specifications defined by the standard:

The 3 specifications that determine a flashout’s light quality:

Light Output IconLight Output – Measured in lumens. The higher this value, the more light ouput from the flashlight’s LED, which can be spilled or ‘flooded’ to illuminate the immediate surroundings, or be channeled into a beam to light up an object at a distance. It also affects the energy consumption levels and amount of heat generated.


Beam Distance IconBeam Distance – Measured in metres. As lux decreases at 4x the rate with each 2x increase in the object’s distance, this is the maximum distance the flashlight can project or ‘throw’ a useful amount of light (defined as the brightness of a full moon on a clear night at 0.25 lux). The higher this value, the further the light can be ‘thrown’.


Peak Beam Intensity IconPeak Beam Intensity – Measured in candela. This is the intensity of the brightest point in the beam. The higher this value, the brighter your flashlight can illuminate the objects you point it at.

Beam Distance and Peak Beam Intensity are related to the focusing optics and reflectors used in the flashlight. They directly augment the flashlight’s efficiency, with some designs being able to produce brighter and more powerful beams and greater ‘throw’ distance using a lower light output. This increases battery life, reduces heat and extends operation hours.

With these specifications, you can go on and define more of what you’re looking for in a tactical flashlight.

  1. Do you need to identify objects in the dark from a large distance?
  2. Do you intend to illuminate a large surrounding area?

Depending on how punishing the environment the flashlight is subjected to operate in, the rest of the other specifications should come in handy in determining its survivability:

Run Time IconRun Time – The time it takes for the light output to drop below 10%, 30 seconds after the flashlight is turned on with fresh batteries. 30 seconds is the approximate time for the LED to warm up and reach its maximum light output.


Impact Resistance IconImpact Resistance – Measured in meters. This is the maximum tested height which the flashlight has been proven to still work and not exhibit any visible cracks or damage, after being dropped and subjected to impact on a concrete surface. This indirectly shows how well the flashlight holds up to a bashing.


Water Resistant IconWater Resistance – Classified as IPX4 (Water Resistant) if the flashlight remains fully functional, 30 minutes after being splashed with water. Wet weather proof basically.



Water Proof IconWater Proof – Classified as IPX7 (Water Proof) if the flashlight can function normally 30 minutes after being submerged 1 meter in water for 30 minutes. Classified as IPX8 (Submersible) if the flashlight can function normally 30 minutes after being submerged in a specified depth of more than a meter for 4 hours. In both cases, water shall not leak into the flashlight and damage the electronics or batteries.

These are definitely useful specifications for those who need to:

  1. Use a flashlight underwater
  2. Use a flashlight for self-defense
  3. Use a flashlight for long hours

As you can see, the ANSI NEMA FL-1 standard helps you to look out for certain features in a flashlight that might best suit you.

Sadly, not all manufacturers go through the hassle and expensive process of benchmarking and publishing these specifications. However, for newer players that do, it could be an indicator whether the manufacturer is serious about flashlights!

Hope this helps you to decide between which flashlights to choose!