Skip to main content

How to Find the Right Flange Size

What is a Flange? 

A breast flange or shield is a plastic funnel that goes directly over your nipple to express breast milk when you are pumping. Flanges are not one size fits all and come in a wide range of sizes from 10mm – 36mm. Most breast pumps will include sizes 24/25mm and 27/28, but you may need a different size based on the measurement of your nipple diameter.  

Pumping should never hurt. If you are experiencing pain, discoloration, or rings around the areola when pumping, it is likely coming from your flange size. Having a poorly sized flange can cause breast damage, reoccurring clogged ducts, and low milk supply, which can lead to premature weaning.  

Correct flange sizing will ensure a comfortable pumping experience and optimal milk output. Other benefits of proper sizing include: 

  • Faster emptying of the breast 
  • Increased milk supply  
  • Improved Suction 
  • Maximize use of breast pump settings & cycles 

How To Measure  

Finding the proper size for a breast flange is based on the diameter of the nipple, not the areola (the softer pigmented skin around the nipple).  We recommend measuring your nipple diameter before nursing or pumping and using a flange size equal to or closest to your nipple diameter.  

Download our helpful nipple diameter ruler here.  

How should my nipple look when pumping? 

When pumping, the entire nipple should fit comfortably without much, if any, of the areola entering the tunnel. Your nipple should stretch a little less than halfway down the flange when pumping. If your nipple is pulling through the entire flange tunnel it could mean you need a different flange size.  

Here are more indicators you may need a new flange size: 

  • Nipple or breast pain when pumping 
  • Ring around base of the nipple 
  • Discoloration of the nipple  
  • Reoccurring clogged ducts 
  • No suction or suction is breaking when pumping
  • Breastmilk dripping from bottom of the flange when pumping  

Sizing options  

Most pumps will include 2 sizes and have at least 2 additional sizes available to purchase separately. Though the brand manufacturer may not offer the size you need, there is likely to be a compatible alternative. A silicone insert can be an option to reduce the flange tunnel. Silicone inserts are readily available and compatible with most breast pump brands.  

You may qualify for additional flanges sizes and accessories through your insurance.  

Click here to learn more