How To Find Your Best Flange Fit
When it comes to pumping, flange fit matters (a lot more than most people realize). The right flange size can make the difference between an efficient, comfortable pumping session and one that leaves you sore, frustrated, and wondering why you’re not getting much milk.
Let’s break down how to find your best fit, and what to look out for if your flange is too large.
Your Best Fit
When you’ve found the right flange size, here’s what you should see and feel:
Only your nipple (not your areola) is pulled into the tunnel.
The sides of your nipple gently touch the tunnel walls.
Your nipple moves slightly back and forth inside the tunnel with each suction.
Milk sprays during pumping, not just drips.
Pumping for 15–20 minutes (both sides at the same time)
Feels comfortable - maybe even like “nothing” or just a gentle tug.
When your flanges fit well, pumping should never feel painful or cause visible damage to your nipples.
Signs Your Flange Is Too Large (or Much Too Large)
If your flange size is too big, you might notice:
Discomfort or pain while pumping
Less milk collected — or milk that only drips instead of sprays
Your nipple moves side to side in the tunnel
Pumping sessions take much longer
Areola tissue gets pulled into the tunnel and may swell
Over time, your nipple may swell or look misshapen after pumping
Many older resources used to recommend a larger flange that pulled in part of the areola — but newer clinical evidence shows that this often leads to swelling, reduced milk output, and nipple damage.
A Few Tips
Measure your nipple diameter (in millimeters) after a pumping session when it’s at its largest. Then add about 1–3 mm to find your ideal flange size.
Keep in mind: you may need different sizes for each breast or as your body changes postpartum.
If you’re struggling to find the right fit, reach out to a lactation consultant for personalized guidance — they can help you measure, fit, and adjust for comfort and milk flow.
Need More Guidance?
We created a comprehensive Lactation Guide ($4.99) packed with trusted, evidence-based information to help you feel confident in your breastfeeding and pumping journey — including flange fitting, storage guidelines, pumping schedules, and more.
And if you’d like personalized, one-on-one support, our IBCLC (International Board Certified Lactation Consultant) is part of the Choose Joy Nursing team and available for both in-person visits in Nashville and virtual consultations.
Because when you’re supported and comfortable, your baby benefits too.
Information adapted from Babies in Common and current lactation research.
