Quick answer

Measure the diameter of your nipple base (excluding the areola) and choose a flange that is 1–3 mm larger. For eufy wearable pumps, use the eufy Sizing Inserts to fine-tune the fit without buying a new flange.

Why flange size matters for comfort and output

A flange that is too small can cause friction, pain, and blocked ducts. A flange that is too large pulls in areolar tissue, reducing suction efficiency and milk output. The correct size keeps the nipple centered and moving freely inside the tunnel.

How nipple size can change over time

Nipple size can fluctuate during your breastfeeding journey due to engorgement, pumping frequency, or weaning. Re-measure every 4–6 weeks or whenever you notice discomfort or a drop in output. The eufy Sizing Inserts let you adjust the fit without replacing the entire flange.

Step-by-step flange sizing guide

  1. Step 1: Measure your nipple base: Use a soft measuring tape or ruler to measure the diameter of your nipple at the base (where it meets the areola). Do not include the areola itself. Measure both nipples—they can differ by 1–2 mm. Common mistake: measuring the areola instead of the nipple base. Check that the ruler touches only the nipple skin.
  2. Step 2: Determine your flange size: Add 1–3 mm to your nipple base measurement. For example, a 15 mm nipple base calls for a 16–18 mm flange tunnel. Most standard flanges come in even sizes (17 mm, 19 mm, 21 mm, etc.). If you are between sizes, choose the smaller one and use a sizing insert to adjust. Checkpoint: If you have eufy wearable pumps, the eufy Sizing Inserts (2-pack) let you fine-tune the fit in 1 mm increments.
  3. Step 3: Test the fit during pumping: Place the flange and start pumping at a low suction level. The nipple should move freely in the tunnel without rubbing the sides. You should see a small amount of areola pulled in—no more than 2–3 mm. If you see excessive areola or feel pinching, the flange is too large or too small. Common mistake: ignoring slight discomfort. Even mild rubbing can cause nipple damage over several sessions. Adjust the fit or insert before your next pump.
  4. Step 4: Adjust with sizing inserts if needed: If the standard flange feels loose or causes friction, insert the eufy Sizing Insert that matches your target size. The soft silicone insert reduces the tunnel diameter slightly, giving you a custom fit without buying a new flange. Checkpoint: Inserts are especially useful when your nipple size changes during the breastfeeding journey.

Product that helps with flange fit

  • eufy Sizing Inserts for All Breast Pump (2-Pack): Perfect Compatibility: Exclusively designed to be fully compatible with eufy Wearable Breast Pumps. Measure your nipple base (excluding the areola) and refer to our sizing guide to ensure the size is right for you. Baby-Safe and Soft Silicone: Crafted from premium, BPA-free, food-grade liquid silicone. These inserts allow you to adjust the flange opening by a few millimeters, so you can get a precise fit without buying a new pump part.

    eufy Sizing Inserts for All Breast Pump (2-Pack)

    eufy Sizing Inserts for All Breast Pump (2-Pack)