FLANGE SIZING 101 | What it is, why it’s important, and how to get it right!

Flange sizing is essential! Did you know that in order to most effectively pump you need to know your flange size? What even IS a flange size? How do you measure it? Is having a small flange size bad? What about a big size?? So many questions! Read on for the top flange sizing questions and answers from expert and IBCLC Allison.

(This blog post was originally a video. Check it out, here!)

As a side note, there is an extensive section on this inside the Pumping for Working Moms Program AND you can get personalized help from Allison (a Lactation Consultant and Breast Pump Expert) with not only flange sizing, but all things pumping!

When I started pumping for the first time, I had no clue that flange sizing was even a thing. To be honest, I barely understood the basics of a breast pump! And, I don’t think I’m alone here!

But thankfully there is so much more information available now that we can learn and share together especially for moms who are trying to combine breastfeeding and pumping together. Pumping can be challenging but knowing your flange size can help you start your pumping journey off right!

-Allison Tolman, IBCLC

Flange Sizing Basics

What is a flange? A flange, sometimes called a breast shield, is the tunnel-like piece that will go around your nipple. The function of a flange is to suction the pump to your nipple to create a vacuum that will extract breast milk.

What is a flange size? The size of the flange is the diameter of the smaller opening in the funnel. It has nothing to do with the size or shape of the outer part, just the diameter of the small hole.

Flanges come in different sizes, like 21 mm, 24 mm, 27 mm etc. Your pump comes with at least one set of flanges, maybe two. But the flange size that comes with your pump may not be the size you need! You determine your flange size by measuring your nipple.

Measuring Your Flange Size

Measuring your nipple can be a little bit confusing. It can be hard to tell where the nipple ends and where the areola starts. But, do your best. Measure around your nipple before the areola starts. This is a useful graphic from Unimom Breast Pumps to help you visualize what you’re trying to do.

Unimom Breast Pumps- https://unimomus.com/pages/breast-shield-sizes

There are measuring tools available that can help you! This one from Legendairy Milk is straight-forward and easy to use. (Use code NEWLITTLELIFE15 for a discount!) You can also find flange sizing rulers on Amazon. A regular ruler or measuring tape will work, too.

Trial and error is another measuring approach. Order a few different flange sizes and test them out. Usually, it’s recommended to use the smallest flange size possible.

One more thing to note, you can be two different sizes on each breast! Don’t be alarmed if you measure one and it’s a different number than the other. Just go from there, this is also super normal.

Other Measuring Methods

There’s a lot of different measuring recommendations out there. Some suggest measuring your nipple and then adding three to four millimeters. This method usually leads to flanges that are too big. But, you won’t know unless you try to give it a shot. See if it’s more comfortable, see if you get more milk.

Typically it’s best to use the harder flanges that your pump company makes. But, you can get silicone inserts to help you with sizing. These inserts work by taking a flange that’s too big and then adding the silicone inside to make it a tighter fit. These inserts can be great. Some moms have no trouble with them and it can be an inexpensive way to try some different sizes.

working moms program

Why is Flange Sizing so Important?

Two reasons:

  1. Comfort
  2. Milk Output

First, pumping should never be uncomfortable. Read that again, pumping should never be uncomfortable! The most common reason that moms join the New Little Life Working Moms Program is pumping discomfort. And the first step to managing pumping discomfort is finding the right flange size!

Second, flange sizing can affect milk output. If your flange doesn’t fit well it won’t extract milk correctly. You could get areas of the nipple that aren’t getting milk pulled out because of the way the flange fits.

Avoiding Nipple Damage with the Right Flange Size

An ill-fit flange can also cause damage to the nipple. If your nipple is big and you’re using a flange size that is too small, your nipple is rubbing, pushing and pulling on the inside of the tunnel.

If you’re using a flange size that is too small, the nipple and the areola are getting pulled really far in. There’s just no support for the nipple. The nipple and areola are hanging out in there being stretched and pulled really far which can cause damage, cracks and bleeding. So, it’s really important to get the right flange size so you can protect your nipples!

Does the Size of your Breast Affect Flange Size?

Do bigger breasts require bigger flange sizes? NO! The only thing that matters is the nipple size! It does not matter if your areola is tiny or big or if your breasts are small or large. There are so many different combinations of breast and nipple from very tiny nipples on very large breasts to very large nipples on really tiny breasts. It really doesn’t matter! Use the tips above to accurately measure your nipple, because that’s what DOES matter in flange sizing.

My Flange Size is Working, Why Should I Change?

“I can get milk out with the flanges that came with the pump, so why bother measuring my flange size?” Because an accurate flange size will help you pump more efficiently!

The amount of milk and how quickly you can pump it out is affected by flange size. The right flange size will provide better suction and more comfort, too!

So, you may be getting some milk out with with the flanges you didn’t measure, but you will be surprised at how much faster and easier you can get more milk out with the right flange size!

A Note about Flange Sizing and Milk Output

Remember, you may not know how much more milk is available to you until you actually try the right flange size. Members of the New Little Life Working Moms Program usually start off saying that their milk output is fine, but once they get fitted with their right flange size, these moms find that their milk output is much better! All this to say, you might not even realize how your flange size is affecting you until you try a more accurate one!


What About Elastic Nipples?

What even is an elastic nipple?? So, we all have elasticity in our skin. Some people have extra elasticity. Extra elasticity can make your nipples stretch really far and cause weird things in pumping. Your breast is designed to stretch some, but elastic nipples stretch EXTRA far.

If your nipple is stretching really far and you’re absolutely sure that you have the right flange size, you might have elastic nipples.

But, here’s the thing. Some people who think they have elastic nipples are really just using the wrong flange size! A flange that is too big can cause your nipple to pull all the way to the end of the flange, like an elastic nipple might. Elastic nipples are definitely a thing, but they may not be a thing for you! Make sure to measure your nipple for the right flange size. If you’re having trouble measuring, talk with a lactation consultant!


You Can Do It!

Flange sizing is pretty straight forward. Measure your nipple, or try a few different sizes, but make sure that you have a good fit! Hopefully this post has convinced you that flange sizing can make a big difference in your pumping experience. You can do this! You can find the right size and be on your way to a great pumping journey!

Schedule a call with our team to see if you’re a good fit for the Pumping for Working Moms Program

FLANGE SIZING 101 | What it is, why it\'s important, and how to get it right!