How to measure lumens?

  • How much light do you need?
  • Are you getting sufficient or too much of it?

Indeed, answering these questions will be an uphill task for many people. That is because unless you understand how many lumens a given lighting projects, you can never be too sure. Lumens are the SI unit that highlights the flow of light.

Our biggest concern would, however, be how to get the number of these lumens. Well, here is how to measure lumens.

What are Lumens?

Lumens are the units of measurement that we use to determine how bright, or how much illumination, a light has. Lumens can be defined as the visual light that a bulb emits, and should not be confused with the wattage; which is the amount of energy used to power the lightbulb.

That said, both are integral aspects of how light bulbs function and it is important to understand how each works in conjunction with each other.

Lumens measure the amount of light that a bulb produces, so the higher lumens translates to more light that is produced. To make it easy to remember, the term lumen literally does translate to light.

While this is not a new term to describe the amount of light that a bulb produces, you may notice that it is becoming the most common term used, instead of wattage.

We will go further in-depth on how wattage relates to lumens below. However, it is important to keep in mind that lumens will not change depending on the type of bulb that is used; 100 lumens is the same amount of light regardless of how much energy is used to power the light.


How are Lumens Calculated?

how to measure lumens

Lumens are calculated by converting the number of watts that a lightbulb uses into lumens. This is how they are calculated, and an easy way to think about this is to remember that watts are referring to what goes into a lightbulb to power it, and lumens is what it produces.

That said, this will not be an exact number as lumens refer to how much light is produced, not the amount of energy that is used to power a bulb.

The reason behind using lumens to measure the light output for lights is because it has been determined that it is the best way to measure how efficient the lightbulb is.

Luckily for us, there is a relatively simple way to determine and translate the strength of lumens. Simply put, there is an easy ratio that determines how much lumens per wattage a lightbulb will have.

However, this ratio will change depending on the type of bulb, as some are much more energy-efficient than others.

For a traditional incandescent bulb, this is a 16:1 ratio, meaning that each watt will produce 16 lumens. So for instance, if a lightbulb uses 60 watts to turn on, then it will produce 960 lumens.

For your reference, here is a list of the most common bulbs and their wattage to lumen ratios:

  • LED bulbs: 73:1 (73 lumens per 1 watt)
  • Halogen bulbs: 22:1 (22 lumens per 1 watt)
  • Fluorescent bulbs: 61:1 (61 lumens per watt)

What does this process entail?

The intensity of light emitted from a specific surface per unit area is what matters most in measuring lumens. It is what we call luminance. This aspect comes in units of cd/m2, where one cd/m2 is equivalent to a unit of luminance (nit). Cd stands for candela, a which is a vital element in measuring light intensity.

Usually, you will be able to detect how much lumens a light emits by noting the charge they leave on a surface. For instance, the more light that strikes a given surface, the more charge gets built up. If a given wavelength seems to leave more charge, it means that it comes with higher lumens.

You will be free to use either a lux meter or a light meter when measuring your light intensity. A light meter is relatively easy to use, as you will only need to put it on a surface where the light will get reflected. Ensure that the meter is on the surface, as this will enhance the level of accuracy you get in the long run.

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You could also rely on LED light meters to get your readings. Besides, you can hardly ignore the popularity that these meters are currently enjoying. They will come in handy in measuring the light intensity of up to 500 lux, which is significantly notable.

Notably, measuring lumens could be a daunting task. That is because you will need lab tests for you to come up with accurate figures. However, it is much easier to understand how many lumens will be ideal for your lighting. Here are a few variables that you will need to take into account in this regard.


When to measure lumens?

Various reasons could push you to measure lumens. Well, in most cases, you will need to measure lumens in these situations.

  • Safety

There are instances when minimum levels of illumination in specific environments. As such, you will need to be sure of the light intensity within your surrounding by taking this measurement.

  • Monitoring weather

Most often, it will be essential to map out light intensities in specific regions. It will help in understanding the optimal weather or even light that a day will get subjected to.

  • Photography

Indeed, the quality of a photoshoot will be dependent on the current light intensity. Unless you take the photo under conducive lighting, you will hardly get the type of results you so desire.

As you look forward to getting the right lumen measurement, you will find the insights mentioned above vital.


How strong are 100 lumens?

100 lumens is going to be fairly dim; because as we mentioned above, lumens are calculated differently from wattage. As an example, a 100-lumen light bulb will only provide around the amount of light that you would expect from a flashlight or a solar-paneled walkway light.

100 watts may seem to be like a bright light, but because lumens are measured differently 100 lumens is not very bright. This way of measuring may take some time to get used to, but once you do it makes more sense to measure light this way.


How many lumens are considered bright?

Taking an office light for example (which is bright enough to see what you are working on), they will generally be anywhere between 1000-3000 lumens per bulb.

This is considered to be a bright light for many and is a good place to start if you are looking to brighten up your room or working space.

Above we mentioned the conversion rate for lumens from watts. It should be kept in mind that 1 lumen will be the same regardless of if you are using an energy-efficient bulb or not.

The overall brightness in a room will be determined by how big the room is, how much light fixtures and bulbs you have, and how much lumens are throughout.

For instance, if you have a 100-square foot room then you will want to have around 1,000-2,000 lumens for a good amount of light.


How many lumens do I need?

In this section, we will be going over some common living spaces and areas that you may be wondering about how many lumens you should have.

This is a common question that a lot of people have, and this should help you to understand and determine what is the best amount of lighting for each particular room.

While this is a great starting point for reference, there are other variables that you should take into consideration, such as where the overhead light is located and natural lighting in the room.

#1. For garage

Garages are going to be a little bit trickier than others in determining your needed light fixtures and lumens. This is simply because of how versatile they are, and how they can range in size drastically. To make it easier, we will assume that the garage is just for parking your car and storing items.

While some garages may double as project working areas for around the home, we will add that into the “shop” section listed below.

Now for a normal 2-car garage, it is a general rule of thumb that they will be around 580 square feet. Going off of what we know is necessary for this amount of square feet, anywhere between 1000-1500 lumens would be adequate.

It would be wise to keep in mind that this size for a garage is the bare minimum to fit 2 cars, and yours may be larger. As you can expect, larger garage sizes will require more lumens.

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#2. For shop

Shops will require more lumens than most rooms, simply because you are going to be needing to see very clearly what you are working on. Because of this, you will want more task lighting.

Task lighting will generally be more concentrated and brighter, with full-spectrum color temperature. Most shops are relatively small, only measuring around 400 square feet (excluding commercial size workshops).

Because of this size, it may not seem like you need a lot of lumens. However, you will want to have around 1000-1500 total overhead, with around the same in task lighting over your working space.

This will allow you to see what you are working on, as well as provide the necessary ambient light.

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#3. For bedroom

Bedrooms will vary in size depending on what it is designed for (either master or kid’s bedroom), as well as the overall size of your home.

While it is a good idea to also take into consideration the amount of natural light that you have in the room, it is also good to remember that this is only for a few hours per day.

For most bedrooms that are not extremely large, 1,000- 2,000 lumens is a good amount. If more is needed for your specific needs, it is possible to add other forms of lighting such as lamps.

>> Take a look at the Ultra Guide to the best bedroom lamps

#4. For living room

Many living rooms will now feature a kitchen as well, often referred to as a great room. Because of this, we will list two possible living room sizes as well as the number of lumens that both options would require. For option number one, we will be assuming that the living room is a separate room from the kitchen.

Going off of this assumption, living rooms will generally be around 300-500 square feet, and thus will require around 1,000-2,000 lumens to see adequately.

For the second option, we will assume that the living room and kitchen are connected. Most kitchens will be around 100-200 square feet. While this may not seem like you need a lot of lumens for this size, kitchens you will generally want to be brighter as they are a gathering area and you will be doing food preparation and cooking.

Because of this, if you have a great room that has both the kitchen and living room connected, it is recommended to have around 2,000-4,500 lumens.

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#5. For office

Like workshops, offices will require more lumens as you will need to see what you are working on and reading. Most offices will be around 150-300 square feet.

Again, this may not seem like a lot of light is needed but you will want to have more than would usually be necessary for the size. A good amount of lumens for an office would be in the range of 2,000-3,000.

>> Take a look at Full Reviews of the Best Light for Offices

#6. For kitchen

As we touched on above, you will want to have more light in the kitchen because of the activities taking place in this room.

Most kitchens do not need to be large, but every surface should have adequate light to see what you are doing; especially if the dining room is either right off or connected to the kitchen.

A good rule of thumb for kitchen lighting and lumens is around 2,000-3,000 lumens.

Best Price – Westinghouse Lighting Island Light for Kitchen and Dining Room

#7. For bathroom

Bathrooms are very small in most cases but will require a lot of light. This is where you will be getting ready to present yourself to the world, so you want to make sure that you can see clearly as you are getting ready.

For this reason, you will want to have around 1,500-2,000 lumens. This can change depending on the size of the bathroom, as master bathrooms will generally be larger and require more lighting.

Best for Bathroom – WYZM 2 Pack LED Panel Light

Related Reading:

>> How many lumens for a desk lamp?

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