How to Measure Flange Size + Free Printable Ruler
When it comes to finding the right flange for your breast pump, there’s more than meets the eye. In this article, you will learn about how to measure flange size, different methods for doing so, and how to find the perfect flange fit.
There are a lot of different steps to consider when you are trying to find the right-sized flange for your breast pump.
Having the right-sized flange can make a huge difference in your pumping journey.
Your nipple measurement can be the first step but knowing how to do that can be tricky.
In this article, I’ll share a flange sizing guide, flange chart, and tips for getting the right fit. Flange sizing does matter and is impactful on your pumping journey.
Hi! 👋 I’m Katie, an International Board Certified Lactation Consultant I have helped thousands of moms across the world navigate their breastfeeding journey since 2015. I can’t wait to help you! Be sure to consider checking out my 1:1 lactation support services or enrolling in one of our online breastfeeding workshops today.
How to Measure Nipple for Flange:
It’s MORE than just your nipple size!
Finding the right size flange is more than just taking a measurement. You have to take into account anatomy, elasticity, and the type of flange being used.
Some lactation consultants don’t even recommend measuring. I personally find it helpful to, at least, get a ball park range.
If you ask 100 lactation consultants, you’ll get 100 different ways to find the right flange size.
Here are MY basic steps for getting the best measurement:
- Decide on a method for measuring (discussed here)
- Measure BEFORE you pump. You can also measure after you pump to see if there’s a huge difference, which may indicate more elasticity.
- Your nipple should be erect – if it is not, try and stimulate it so you can get an accurate size
- Measure the base of the nipple from one side to the other. Place your nipple on your measuring tool like it’s on the table – you want it to be underneath your nipple.
- Carefully look at the measurement and make sure you are measuring in mm.
- Measure both nipples – they might be different!
- Record the measurement
- Select a flange size from the chart below – I would also pick a size below and above that if possible
- If you don’t have flanges available in the right size, you can purchase off-brand flanges and flange inserts on Amazon. I would purchase a couple of different sizes if you can.
- Pump again and see how it goes. All these questions should be answered affirmatively to know that you have the right size flange (keep in mind it may take a few pumping sessions to resolve all issues, especially if there is nipple damage).
- Do you experience strong sprays of milk?
- Are you comfortable?
- Does your nipple slide in and out of the tube easily, move freely, and doesn’t get sucked to the end (if it does, you may be dealing with elastic nipple tissue)
- Do you “empty” the breast in about 20 minutes or less?
If you’re struggling to do this on your own, be sure to consider booking a pumping consult! You may be able to get six free visits through The Lactation Network.
How to Measure Flange Size for Pumping
Finding the right size flange for your pump can make or break your experience. Here is a simple how-to guide to find the correct flange size.
Materials
Tools
- Breast Pump
- Measuring Tool
- Flanges
Instructions
- Decide on a method for pumping (discussed here)
- Measure BEFORE you pump – some do recommend measuring afterward, but I would only do this if you are experiencing pumping issues.
- Your nipple should be erect – if it is not, try and stimulate it so you can get an accurate size
- Measure the base of the nipple from one side to the other. Place your nipple on your measuring tool like it’s on the table – you want it to be underneath your nipple.
- Carefully look at the measurement and make sure you are measuring in mm.
- Measure both nipples – they might be different!
- Record the measurement
- Select a flange size from the chart below – I would also pick a size below and above that if possible
- Pump again and see how it goes. All these questions should be answered affirmatively to know that you have the right size flange (keep in mind it may take a few pumping sessions to resolve all issues, especially if there is nipple damage).
- Do you experience strong sprays of milk?
- Are you comfortable?
- Does your nipple slide in and out of the tube easily and doesn’t get sucked to the end (if it does, you may be dealing with elastic nipple tissue)
- Do you “empty” the breast in about 20 minutes or less?
Flange Size Chart
While I used to recommend adding 3-4mm to your measurement, I actually now recommend just 0-2mm. However, there is debate on this in the lactation community. Here is a flange size chart that is in the middle of that and adds 2-3 mm to give you a starting point of what breast shield you should use.
| NIPPLE MEASUREMENT | FLANGE SIZE |
| >10mm | 10mm |
| 10mm | 12mm |
| 11mm | 13mm |
| 12mm | 15mm |
| 13mm | 15mm |
| 14mm | 17mm |
| 15mm | 17mm |
| 16mm | 17mm |
| 17mm | 19mm |
| 18mm | 20mm |
| 19mm | 21mm |
| 20mm | 23mm |
| 21mm | 23mm |
| 22mm | 24mm |
| 23mm | 24mm |
| 24mm | 27mm |
| 25mm | 27mm |
| 26mm | 28mm |
| 27mm | 30mm |
| 28mm | 30mm |
| 29mm | 32mm |
| 30mm | 32mm |
I suggest buying flanges the same measurement as your nipples and one size up to see what feels the best – the best fit is a comfortable flange, allows you to have strong and frequent sprays, and yields the most milk possible for you. You can find places that sell smaller flange sizes here.
Free Printable Flange Size Ruler
I have two different printable options for you!
The first is a printable paper caliper that my husband designed. I find it better than just a regular ruler since you can adjust it to fit your nipple.
The second is a circle-style measurement tool. You have to cut out the holes, but it generally works pretty well.
You can enter your email below to get a copy of both sent straight to your email, along with details on how to use it.
Methods for Measuring Nipple Flange Size
Circular Diameter Ruler
- PACKAGE QUANTITY -- 4 pieces of rulers in different colors, which can fully meet your daily needs.
- SUPERIOR MATERIAL -- Made out of high quality plastic, will not bend and broken easily.
- COLOR -- Blue/Green/Yellow/Rosa Red for you to choose. Kids will like these colourful rulers.
- DIMENSIONS -- Circle Diameter: 2-40mm; Rulers Measuring Scale: 0-20cm. Ruler Size: 21.5 * 10.5cm(L*W).
- APLICATION -- Can use as normal ruler, and can also draw ten million different decorative pattern curve pattern.
One measure your flange size is with a circular ruler. I really like using these! There are some companies that have made some specially branded ones for breastfeeding, but honestly, you can grab a three-pack on Amazon or even at your local hardware shop.
What I like about these is that you can put your nipple inside the circle. I find it to be pretty accurate. You want your nipple to be snug but not stuck or rubbing. You can also use the traditional ruler on it to double-check.
Traditional Ruler:
You can also use a traditional ruler to measure your flange size. Keep in mind that since this will likely be in cm, you will need to convert to mm.
Measuring Tape:
A measuring tape can work to measure your nipples as well. The one caveat I will put in for this one is that sometimes measuring tapes will stretch out, so they aren’t always as accurate.
Digital Caliper:
- Precise measurement: Measurement range: 0 - 6''/ 0 - 150mm; Resolution: 0.01”/ 0.1mm; Accuracy: ±0.2mm/0.01”. Perfect and accurate caliper measuring tool for household/DIY measurement. Please choose stainless steel digital caliper for more accurate measuring
- 4 measuring modes: This digital caliper can be used to Measure inside and outside diameter, depth and step with two sets of jaws and a probe. Powered by battery, comes with a pre-installed battery and a spare battery
- Inch/mm conversion: One button quick switch between two units: inch and millimeter, definitely save your time. The buttons are made of rugged plastic carbon fiber composites, durable and portable
- Zero setting function: The smart design allows you to set zero with an easy touch of a button and start a new measurement at any point of the scale, ideal for differential measuring
- Large LCD screen & auto off: The large and easy-to-read LCD display helps you get precise results quickly and easily, auto shutdown for saving battery after 5 minutes if without operation
The most precise way to measure your flange size is with a digital caliper. This tool measures the dimensions of an object in millimeters or inches. If you have a digital caliper, you can use it to measure the diameter of your nipples very accurately. I wouldn’t go out and buy one of these (unless you really want to), but if you have one laying around, it can be really helpful!
FAQs about Flange Sizing
If you are planning to pump soon after birth, this would be a good idea so you can have a baseline. Keep in mind that many mothers see their nipple size change after the baby is here.
Yes, it can. If you notice an increase in pain, efficiency, or time spent pumping, you may want to measure again.
There is debate on this. I personally do it before, but you can try both and see if there’s a huge change in the nipple size.
Many off-brand flanges are available that may be compatible with your pump, and these can often be found on Amazon. Flange inserts can also be a good option.
We hope that this article has helped you determine your flange size and find the right-sized flange for your breast pump. If you have any questions, please don’t hesitate to contact us!
Click here to download our free printable flange-size ruler!
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Katie Clark is an International Board Certified Lactation Consultant (IBCLC). She has helped thousands of mothers and families around the globe navigate breastfeeding challenges and questions since 2015. She has a passion for creating research-based, helpful breastfeeding education and helping parents find a way to make breastfeeding work for them. Katie is a mom of three little boys and lives in the great state of Colorado. She also has a degree in Communications with an emphasis in print journalism.
This is a great post! I was looking for a free flange size ruler and this is perfect!
I’m so glad it was helpful!