Know you Breast Pump Flange
How to Know Your Correct Flange Size
The flange is the funnel part of a breast pump that fits over your nipple, and its size refers to the diameter of the tunnel opening (measured in millimeters). Choosing the correct flange size is important because it helps you pump more comfortably, improves milk output, and prevents nipple pain, swelling, and possible damage during pumping.
STEP 1: Measure your nipple (BEFORE pumping or latching)
📌 This is the most important step
Measure only the nipple, not the areola (brown part).
🕒 Best time:
Before pumping or breastfeeding, or
At least 30 minutes after your last session
Ways to Measure Your Nipple
You can use either of the following:
✅ Option A: Using a Ruler (mm)
Use a ruler with millimeter (mm) markings
Stand in front of a mirror
Measure straight across the widest part of the nipple
Do NOT include the areola
✏️ Write down the measurement in mm
✅ Option B: Using a Nipple Ruler / Size Guide
Place the nipple into the circle holes
The hole that fits snugly without squeezing is your nipple size
Make sure only the nipple fits, not the areola
✏️ Note the size in mm
STEP 2: Add allowance (very important)
After measuring, add 1–3 mm to get your flange size.
Formula:
Nipple size + 1–3 mm = Flange size
Example:
Nipple measures 16 mm
Add 2 mm
Suggested flange size: 18 mm
STEP 3: Choose the nearest available size
Common flange sizes: 17 mm, 19 mm, 21 mm, 24 mm, 27 mm
If you’re in between:
Sensitive nipples / swelling easily → choose the smaller
Feeling pinching or rubbing → choose the bigger
STEP 4: Pump & do a FIT CHECK (after pumping)
📌 After pumping is for checking fit — not for measuring size
✅ Correct flange fit looks like:
Nipple moves freely in the tunnel
Minimal areola pulled in
No rubbing on tunnel walls
No pain (gentle pulling is normal)
Nipple stays round after pumping
Good milk flow
❌ Too SMALL if you notice:
Rubbing or pinching
Lipstick-shaped nipple
Redness, blisters, cracks
Low output despite strong suction
❌ Too BIG if you notice:
Too much areola pulled in
Puffy or swollen areola after pumping
Strong pulling feeling on the whole breast
Inconsistent milk flow
STEP 5: Re-measure when needed
Your flange size may change over time, especially during the early postpartum weeks, on engorgement days, if pumping becomes painful again, or if your milk output suddenly drops. Re-measure anytime your comfort changes. In our shop, available flange inserts are 13 mm, 15 mm, 17 mm, 19 mm, and 21 mm. If you need more help choosing the right size, feel free to message us at babeeboo.ph@gmail.com
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