Sizing with Willow is different than sizing with traditional wall pumps.
It’s important to measure to make sure you have the right size for Willow - when your pump flange fits properly, you get more comfort, a better latch and more milk output. To determine your nipple size we suggest either printing our Sizing Tool or using one of these free ruler apps for iOS or Android.
Size with a Mobile App
To find your flange size using a mobile ruler app, first stimulate your nipple so it perks up. With the app open on your screen, place your phone screen perpendicular to your nipple so you can look down at your nipple against the screen.
One edge of your nipple should line up with the zero on your screen. Slide the measurement bar on your screen to the opposite side of your nipple - that's your nipple measurement!
Now that you have your size, we suggest you use a flange that's 2 - 4mm larger than your nipple measurement.
Size with our Printable Tool
To size with our printable Sizing Tool, cut around the outside of the tool and fold twice.
Stimulate your nipple to perk it up. Slide the paper ruler against your nipple until it is nestled in the corner. Taking a picture or looking in a mirror may help you to see your nipple measurement.
Use a flange that is 2 - 4mm larger than your nipple measurement.
Additional Sizing Resources
What should I do if I'm between Willow®'s sizes?
Does Willow® work for all breast sizes?