A Complete Guide to Eyelash Extension Size and Weight

Eyelash extensions are among the hottest things in the beauty world right now, and for lash artists it’s of utmost importance to know all the most essential information about them in order to apply them successfully.

We all must have seen someone with an amazing flutter that leaves everyone wondering how they managed to get such lovely lashes! For our clients, this is usually the case. Lash artists both were and are clients as well, and seeing the different styles available for different dimension lashes with different size and weight can really put us in the mindset to figure out how each extension is applied.

Eyelash extensions help a lot of people in achieving a kind of dramatic look that doesn’t require any makeup at all. Indeed, many do opt for getting eyelash extensions instead of makeup because of that flexibility, since they can adjust and tweak them until their favorite look is attained. This is one of the trump cards that can really make eyelash extensions become more and more favored by clients and beauty workers alike. 

In this article we will proceed to provide you with the most complete guide to help you always be able to choose the best eyelash extension for your clients. 


In order to understand what actually constitutes eyelash extensions, first we must understand the importance of the dimension of a respective lash. Different dimension lashes will result in different methods of application, and this will prove crucial in practice.

Dimension lashes are very situational, and therefore they require substantial knowledge as well as quick thinking in order to reach a decision on which one of them to apply for your client.

Types of dimension

Generally, we have four types of dimensions: Basic; Volume; Mega; Special. We will delve into each of them for more specifics. 

Basic: 1D (single)

These are some of the most commonly used lash extensions out there, because they are relatively lightweight and don’t cause too much of a risk of brittlement or breaking. 

The first of them all is the classic extension, also sometimes called the 1D extension. The D here refers to the number of lashes applied to a natural lash at one time; a lot of lash artists call this the 1:1 ratio, where a single lash extension is applied to one natural lash.

The basic eyelash extensions besides 1D are favored for their lightweightness and typically used for even clients with sparse natural lashes. They will give the clients a softer, fluffier look that really lasts. 

Generally speaking, however, 1D lashes can really help as well if you really know your game and are painstaking during applications. Overall, basic lashes will help emphasize low density natural lashes, while also being suitable for a more varied set of natural lashes as well.

Volume:  3D to 9D 

Volume eyelash extensions or volume fans refer to 3D, 4D, 5D and 6D, in other words,  1:3, 1:4, 1:5 and 1:6 ratios, where 3 to 6 strands of eyelash extensions are applied to the clients’ natural lashes.

 LLBA L Curl

LLBA L Curl 

Volume: 10D, 12D, 14D

Volume lashes are those that range from 10D and up, and typically bonded together using a fan. The way to determine their ratios is the same as with basic lash extensions; for example, 10D means dimension lashes with a ratio of 1:10, as in you apply 10 lash extensions at once to one single natural lash.

The case is similar for 12D and 14D eyelash extensions as well. Since these have higher ratios than the basic ones, they offer higher volumes and a more dramatic look once applied. There’s a misleading conception that volume eyelash extensions offer a fake look, but this shouldn’t always be the case.

True lash artists know that one should always apply lash extensions to match with the client’s natural lash, or at the very least should be able to determine the correct volume and thickness and tweak accordingly. Volume lash extensions are for when clients need extra volume and thickness, and that they have fine natural lashes able to support the extensions.

Occasionally clients will ask us to apply for them the thickest volume lashes possible, and this is when you will have to yield. But generally speaking, volume eyelash extensions applications can vary: to produce a more natural look, to simply add extra volume and length, or to turn out a dramatic, full volume look.

In terms of being dramatic though, nothing can really top Mega lashes.

Mega: 10D, ... , 20D

At times our clients will want very, very high volumes. We are talking about 16D to 20D lashes, meaning a 1:16 and up ratio. For example, in the case of 16D lashes, you have to apply 16 extensions onto one single, natural lash. 

These are called mega volume lashes. They are often not talked about as much as others but they do get used, and it’s important that you know what they are first before stumbling upon them in practice. 

Such high volumes aren’t really used in isolation but rather in a hybrid set with other types of lashes and ratios. However, from time to time, lash artists do receive requests to apply them as a uniform set. Be calm and try to communicate with your clients first about the possible risks of applying really high volume extensions; afterwards, it depends on your expertise to make sure that the client receives the best possible service.

These mega volume lashes, needless to say, will give you a very, very dramatic look. You will most likely be the center of attention everywhere you go after application. If this is something that the client signs up for, we must do our best to guarantee that the look they want is achieved. 

Remember not to think of mega volume lashes as giving a “falsie” look, but rather that we’re satisfying our clients with our top-tier services. 

Eyelash extension thickness and weight

Eyelash extension thicknesses range from 0.03mm to 0.30mm. Among that, 0.03mm, 0.05mm and 0.07mm are extremely thin and lightweight. You can use them for clients with very thin natural lashes, or for 2D-6D lashes and fill in gaps. 

0.10mm can be used for classic or volume 2D, applying on thinner very fine natural lashes. For thinner lashes or to make a soft look, you can use 0.12mm. 

The 0.15mm thickness is to create a natural thicker look while 0.20mm will bring a natural mascara look for the eyes. For a glamorous look, you can use 0.25mm but it might be a bit heavy. Those who own strong and thick natural lashes can try 0.30mm to have an extreme look.

This we have already covered thoroughly in “Lash extensions size guide”, and it’s just as important that you take a look at the article as well in order to receive complete information and recommendations. 

Making your own fans

When you buy premade fans, single lashes are bonded together in order to create the fans - eyelash extensions with more than one lash. Oftentimes, the methods to stick the lashes together are heat and glue. Glue bonding uses a specific kind of adhesive to bond the lashes and form a fan, and is generally heavy and can add extra weight to the natural lashes. Heat bonding is much more satisfying. Using this method, fans are sealed via heat, which means much lighter weight and more comfort. The method is favored both by beginners and practicing pros alike. 

It’s obvious that you can make your own fans. However, t is a tough task and requires the most excellent skills from the artists as well as top-tier skills. There are two main ways of making fans by yourself, using a method called the pinch method and using tweezers.

 Making fans

In the pinch method, you use your fingers to pinch the base of a lash group (after picking them up with a tweezer). Afterwards, you rotate them into a fan very gently like until they stick together. Only then can you apply them to the natural lash. 

The process is similar with tweezers, but in this case you use a pair of tweezers, one to pick the lashes up and one to join them together at the base. Afterwards you either dip them into adhesives or employ other relevant methods such as push and bloom, lean and pick up, roll them in the fan, etc.

How to choose the right size for a lash set

Choosing the right D

The right diameter will largely determine the durability of the extension as well, since the higher the diameter, the heavier and thicker the extensions get. You don’t want something that your natural lashes can’t support at all. 

The rule of thumb for choosing the right diameter is taking measurements of the natural lashes of your clients, then promptly match the diameters. Generally speaking, it’s permissible to go slightly thicker than the natural lashes to produce a more dramatic look, but you should really be careful—because if this is overdone, the result will be an extreme look, and there will be a risk of breakage.

Choosing the right length

This is one if not the most important things for you to do as a lash artist: determining firsthand what the correct length for your eyelash extension is. Do this wrong and the entire procedure will be in jeopardy. 

Most salons offer eyelash extension lengths from 9 mm to 20 mm, which can accommodate clients with a wide variety of natural lash types. Remember to go for longer, thicker lash extensions if they have naturally long, thick lashes, and similar shorter ones for sparse natural lashes. 

Also try to determine if the clients’ natural lashes can really support the weight of the extensions. Sometimes just matching lengths is not enough. You will have to measure the weight and, as has been mentioned in the previous section, the diameter as well, to produce long lasting effects. A lash serum can be used to add extra durability in this case. 

Mix different sizes together

We have another way to apply lashes, which is mixing lashes of different sizes together to produce a set. This is called a hybrid lash set, which generally consists of both classic lashes as well as volume lashes. Usually in a set like there are more classic lashes than volume ones, but this is adjustable. 

Hybrid lash sets are often used situationally and require expert hands, but usually they are employed for clients who want more texture and volume but without the at times false, unnatural look that volume lashes can have. 

Hybrid lash extensions offer a wide variety of benefits that classic lash or volume lash extensions can’t offer on their own. They really are the best of both worlds. There’s a reason they are Kim K’s favorite lash extensions. 

If the client is looking for something that’s more balanced while still improving their lash game, this is absolutely something you should recommend!

Eyelash extensions can be life saving if and when you choose them correctly and consequently apply them properly. This means knowing the right dimension lashes, as well as the right eyelash extension size and weight. It will be a tough task since there are a wide variety of types of lash extensions out there. That’s why it’s always wise to seek fresh perspectives!