SIZING GUIDE

Breast Pump Flange Sizing Guide

Getting the correct flange size is the most important step for a comfortable and effective pumping experience.

WHY IT MATTERS

The Importance of Choosing the Right Breast Pump Flange Size

Getting the correct breast pump flange size is crucial for a successful pumping experience. An ill-fitting flange can lead to a range of issues, including clogged ducts, discomfort, and pinching — none of which are pleasant.

Using a flange that is too small or too large can negatively impact your ability to pump effectively, making it essential to select the right size. To assist you in making the best choice, we've provided a comprehensive flange sizing guide below. Ensure you get the optimal fit for a more comfortable and efficient pumping experience!

Which Part Should You Measure?

Diagram showing nipple and areola area for measurement

Identify the Nipple & Areola Area

Take note of whether you have elastic nipples or not. Measure from nipple to nipple base. Less than 1mm of areola for the exact size. The nipple is the protruding part at the center. The areola is the darker surrounding area. When measuring for your flange, you only need to measure the nipple diameter — not the areola.

Blissbaby Flange Sizing Chart

Add 0-4mm from your exact nipple size to find your recommended flange size.

Nipple Size

Flange Size

10-13mm

14mm

13-15mm

16mm

15-17mm

18mm

16-19mm

20mm

18-21mm

22mm

20-23mm

24mm

How to Measure: 3 Simple Steps

01

Stimulate Your Nipple

Gently roll or massage your nipple for a few seconds to mimic how it looks when erect — this gives a more accurate size, like how it will appear during pumping.

02

Measure Nipple Diameter Only

Use a millimeter ruler or nipple sizing tool. Measure only the nipple, not including the areola (the darker surrounding area). Measure across the base of the nipple (widest part).

Example: If your nipple is 16mm in diameter, write that down. Start from 0cm (1cm = 10mm).

03

Add Buffer to Get Flange Size

Before pumping? Add 2-4mm. After pumping? Add 1-2mm. This gives room for comfort and nipple swelling during pumping.

Example: Nipple diameter = 16mm → Recommended flange size = 18mm or 20mm.

IMPORTANT

Different Sizes Are Normal

It is completely normal if your breasts are different sizes. Your breasts might need a different size flange — you might need to buy one for each side.

Your flange size may also fluctuate as you pump. Remeasure your flange size before replacing breast pump parts to ensure the best fit.

Tip: Re-measure every 1–3 months for the best fit.

Signs You're Using the Right Size

Free Movement

Nipple moves freely inside the tunnel without rubbing against the sides.

Minimal Pull

Minimal areola is pulled into the flange during pumping.

No Pain

No pain, pinching, or rubbing during or after pumping sessions.

Good Flow

Good, consistent milk flow with effective emptying of the breast.

Need Personal Guidance?

Book a free consultation with our certified peer counselor for flange sizing, pump fit, or breastfeeding support. Your comfort and health are our top priority.

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