Breastfeeding is a personal journey, and every mom’s experience is beautifully unique. If you're using a breast pump, there’s one often-overlooked factor that can make a huge difference in your comfort, milk output, and overall pumping experience — flange size.

At BabyBuddha, we understand that successful pumping isn’t just about having a high-quality pump. It’s also about making sure every part fits you perfectly — and the flange size is a game-changer.

In this guide, we’ll help you understand what a breast pump flange is, why the right size matters, how to measure your nipple correctly, and how to choose the best fit for your body.

What Is a Breast Pump Flange?

The flange, also known as a breast shield, is the funnel-shaped part of a breast pump that fits over your nipple and areola. It creates the vacuum seal that allows the pump to extract milk from your breast.

While it may seem like a one-size-fits-all component, the truth is: flange size matters a lot. Using the wrong size can lead to pain, nipple damage, clogged ducts, and reduced milk output.

Why Choosing the Right Flange Size Is So Important

Think of the flange as a pair of shoes. Sure, you can technically walk in shoes that are too tight or too loose — but it won’t be comfortable, and it may cause issues. Similarly, an ill-fitting flange can affect your milk flow, lead to soreness, and make pumping more frustrating than it needs to be.

Here’s how the right flange size helps:

✅ Maximizes milk output

✅ Improves comfort and reduces soreness

✅ Prevents nipple swelling or rubbing

✅ Reduces risk of blocked ducts and mastitis

✅ Encourages longer and more productive pumping sessions

How to Measure for the Correct Flange Size

Finding your correct flange size starts with measuring the diameter of your nipple base — not the areola. You want to measure right after a pumping session or nursing, when your nipple is at its average size.

Step-by-step measurement:

Use a ruler or measuring tape in millimeters (mm).

Measure the diameter of your nipple at the base (not including the areola).

Add 1-3mm to your nipple diameter to get your ideal flange size.? Example: If your nipple measures 18mm, your ideal flange size will likely be 21mm.

Common Flange Sizes:

17mm

19mm

21mm

24mm

27mm

30mm+

Not all pumps include multiple flange sizes, but with BabyBuddha, we offer flexible flange options to suit your unique needs. You can always upgrade or customize with the right accessories from our store.

Signs You’re Using the Wrong Flange Size

It’s not always obvious if your flange isn’t the right size — but your body will send signals. Here’s what to look for:

Too Small:

Nipple rubs against the sides of the tunnel

Pain during pumping

Nipple redness or swelling

Low milk output

Too Large:

Areola gets pulled into the tunnel

Tugging or pulling sensation

Nipple pain or chafing

Milk sprays unevenly or leaks

If you’re experiencing any of these, it’s worth reevaluating your flange size.

Tips for Finding the Right Fit

Every breast is different — even on the same body. Many moms find they need different flange sizes for each breast. Here are some tips to help you:

Use flange sizing tools (printable guides or silicone sizing rings)

Try multiple sizes if you're unsure

Reassess after a few weeks — nipple size can change postpartum

Don’t hesitate to contact a lactation consultant for personalized help

At BabyBuddha, we also offer accessories that allow you to customize your pumping setup, ensuring you’re always comfortable and efficient.

BabyBuddha and the Perfect Flange Fit

We designed the BabyBuddha® Portable Breast Pump to be strong, quiet, and travel-friendly — but we didn’t stop there. Our goal is to support moms in every step of their journey, including helping them find the right flange size for breast pumping.

We offer:

Multiple flange sizes

Comfortable silicone inserts

Expert support for flange sizing

Replacement parts and upgrade kits

Explore our flange options on BabyBuddha Products and make sure you’re not settling for a “good enough” fit — you deserve a perfect fit.

Final Thoughts

The right flange size for your breast pump is not just a detail — it’s the foundation of a successful and comfortable pumping experience. A small adjustment can lead to big changes in how your body responds, how much milk you express, and how you feel emotionally and physically.

If you’ve been struggling with discomfort, low output, or dreading pump sessions, take a moment to check your flange size. You might be surprised at what a difference it can make.