The Easiest Way to Check Your Flange Size

The Easiest Way to Check Your Flange Size

Are you worried about the amount of milk extracted during your pumping sessions? Join the club!  As some point or another, most new moms worry about not having a strong enough milk supply to feed their babies. This concern can escalate if you aren't seeing the milk flow you expect while pumping.

While there are many factors that can lead you to see less milk output than you want or expect to be there, we mamas are often quick to assume one thing: our supply is low. Cue the hasty attempts to do just about anything to increase our supply. We seek out lactation-supporting supplements or add crazy amounts of oatmeal to our diets to try to improve our supply. 


Here's the problem with that approach: 


Low milk supply isn't the only (or even the most common) reason your milk extraction during a pumping session might be low. Before hastily jumping to this conclusion, it is important to ask yourself one question: Am I using the wrong size flange? If you are not using the correct size flange, there is a good chance you have found the source of your problem. A poorly sized flange can definitely cause decreased milk extraction while pumping, so it is essential to make sure you have this right!




When you were unboxing your breast pump, you were most likely provided with two flange options. While this is a hope-filled attempt for you to have a flange that fits, there is a good chance neither of these flanges will be particularly comfortable or effective. (After isn't super realistic that all breastfeeding women everywhere would be able to use the same two sizes of, well, anything.) 

The included breast pump flanges will come in two standard sizes (usually 24 mm or 28 mm); however, the standard size may not be the correct size for you. You may need a different breast flange size than the options that came with your pump. 


You can visually tell whether the sizing of your flange is appropriate or not in the following ways: 


  • Your flange is too small if some or all of your nipple is rubbing against the sides of the flange and there is no space left between your nipple and the flange tunnel while you are pumping.

  • Your flange is too large when there is too much areola being drawn into the flange tunnel with your nipple while pumping. You may see your areola rubbing against the side of the tunnel, and you may see a large amount of space around your nipple in the flange tunnel.

  • Your flange is just right when your nipple can move freely in the flange tunnel. In addition to this, you can see space around your nipple without there being too much of your areola being drawn into the flange tunnel while you are pumping.


Here is a quick visual reference on what exactly I mean: 



If you find yourself needing different flange sizes than the standard provided sizes, don’t worry! Finding the right flange size is a simple process. In this video, I cover the three easy ways to find the right flange size for you...OR you can read all about it down below! 



The first option is a free, “make-it-yourself” paper printable ruler from Legendairy Milk. Instructions on how to construct the ruler are found in your free download and using it is quite easy!

Once you have the ruler constructed you will want to measure your nipple before pumping or breastfeeding, because your nipple will enlarge as you pump or breastfeed. (To pump and then measure would lead to an inaccurate measurement, an inaccurate flange size, and leave you with the same problem as before.) 

Place the ruler gently at the base of your nipple and arrange the ruler arms directly around each side of your nipple without sandwiching it. After you have taken your measurement, you will want to choose a flange size that has an internal diameter that is 2-3 mm at most larger than your nipple diameter. Many flanges also come with different manufacturer recommendations. It will always be in your best interest to verify the manufacturer's recommendations too!




The second option is to use a metric nipple ruler like the one linked here. To use it, you can simply begin trying to comfortably place your nipple within the different-sized holes. You will want to make sure that you are placing the metric ruler at the base of the nipple to ensure an accurate measurement.


If the hole is too small, then you will find that your nipple will be getting caught on the ruler. If the measured hole is too large, then you will find yourself with “wiggle room” and have some additional room around your nipple. When the nipple size is just right, you will be able to insert your nipple into the hole without any additional space. Once you have found the perfect measurement, you may simply add 2 mm and- viola!-  you’ve just gotten closer to your correct flange size! Remember ultimately your comfort comes first, by starting with this measurement as your baseline you're that much closer to having the perfect fit!




If you find yourself needing a different flange size than the ones provided with your pump, there are plenty of options! Manufacturers such as Maymom, Pumpin Pals, and LacTeck offer flanges from 15 mm to 36 mm. Truly, there are different sizes for every pumping mom. In my Amazon store, I have also compiled a selection of commonly desired sizes for your convenience!⠀⠀
Now you might ask, how do I ‘hack’ these other options with the flanges I originally received? Easy, you may not be able to use the original setup packaged with your pump- but with the right pieces you should be able to mix and match what you need to fit your current pump. ⠀⠀

For tips and suggestions for hacking the pump parts you've already got, check out this blog post! 

Remember, pumping should not hurt! 

​If you are...
  • Consistently uncomfortable during your pumping experience
  • Taking too long to empty your breasts fully of breastmilk
  • Struggling with nipple damage that is not subsiding 
  • Or your nipples are sucking into the distance of the flange tunnel

It's a good idea to reevaluate your flanges! Making sure you have the right fit can make a world of difference in your pumping journey. 

 Happy pumping!⠀⠀

Looking for more?

Check out these videos with additional breast pump flange-related info and other helpful breastfeeding and pumping tips!⠀


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